diff --git a/pyfstat/grid_based_searches.py b/pyfstat/grid_based_searches.py
index 091b2ae2a977f15832ddc23cd0bd8432220ec75a..feeb97a8c7710ba9ebbdb67a6d87b35e82d9f670 100644
--- a/pyfstat/grid_based_searches.py
+++ b/pyfstat/grid_based_searches.py
@@ -438,6 +438,10 @@ class TransientGridSearch(GridSearch):
             FstatMap = getattr(self.search, 'FstatMap', None)
             thisCand = list(vals) + [detstat]
             if getattr(self, 'transientWindowType', None):
+                if self.tCWFstatMapVersion == 'lal':
+                    F_mn = FstatMap.F_mn.data
+                else:
+                    F_mn = FstatMap.F_mn
                 if self.outputTransientFstatMap:
                     tCWfile = os.path.splitext(self.out_file)[0]+'_tCW_%.16f_%.16f_%.16f_%.16g_%.16g.dat' % (vals[2],vals[5],vals[6],vals[3],vals[4]) # freq alpha delta f1dot f2dot
                     if self.tCWFstatMapVersion == 'lal':
@@ -445,9 +449,8 @@ class TransientGridSearch(GridSearch):
                         lalpulsar.write_transientFstatMap_to_fp ( fo, FstatMap, windowRange, None )
                         del fo # instead of lal.FileClose() which is not SWIG-exported
                     else:
-                        np.savetxt(tCWfile, 2.0*FstatMap.F_mn, delimiter=' ')
-                Fmn = FstatMap.F_mn.data
-                maxidx = np.unravel_index(Fmn.argmax(), Fmn.shape)
+                        np.savetxt(tCWfile, 2.0*F_mn, delimiter=' ')
+                maxidx = np.unravel_index(F_mn.argmax(), F_mn.shape)
                 thisCand += [windowRange.t0+maxidx[0]*windowRange.dt0,
                              windowRange.tau+maxidx[1]*windowRange.dtau]
             data.append(thisCand)
diff --git a/pyfstat/pyCUDAkernels/cudaTransientFstatExpWindow.cu b/pyfstat/pyCUDAkernels/cudaTransientFstatExpWindow.cu
new file mode 100644
index 0000000000000000000000000000000000000000..28b9d8e288f142a8d4222adb56709ef561599ef4
--- /dev/null
+++ b/pyfstat/pyCUDAkernels/cudaTransientFstatExpWindow.cu
@@ -0,0 +1,122 @@
+__global__ void cudaTransientFstatExpWindow ( float *input,
+                                              unsigned int numAtoms,
+                                              unsigned int TAtom,
+                                              unsigned int t0_data,
+                                              unsigned int win_t0,
+                                              unsigned int win_dt0,
+                                              unsigned int win_tau,
+                                              unsigned int win_dtau,
+                                              unsigned int Fmn_rows,
+                                              unsigned int Fmn_cols,
+                                              float *Fmn
+                                            )
+{
+
+  /* match CUDA thread indexing and high-level (t0,tau) indexing */
+  unsigned int m         = blockDim.x * blockIdx.x + threadIdx.x; // t0:  row
+  unsigned int n         = blockDim.y * blockIdx.y + threadIdx.y; // tau: column
+  /* unraveled 1D index for 2D output array */
+  unsigned int outidx    = Fmn_cols * m + n;
+
+  /* hardcoded copy from lalpulsar */
+  unsigned int TRANSIENT_EXP_EFOLDING = 3;
+
+  if ( (m < Fmn_rows) && (n < Fmn_cols) ) {
+
+    /* compute Fstat-atom index i_t0 in [0, numAtoms) */
+    unsigned int TAtomHalf = TAtom/2; // integer division
+    unsigned int t0 = win_t0 + m * win_dt0;
+    int i_tmp = ( t0 - t0_data + TAtomHalf ) / TAtom; // integer round: floor(x+0.5)
+    if ( i_tmp < 0 ) {
+        i_tmp = 0;
+    }
+    unsigned int i_t0 = (unsigned int)i_tmp;
+    if ( i_t0 >= numAtoms ) {
+        i_t0 = numAtoms - 1;
+    }
+
+    /* translate n into an atoms end-index for this search interval [t0, t0+Tcoh],
+     * giving the index range of atoms to sum over
+     */
+    unsigned int tau = win_tau + n * win_dtau;
+
+    /* get end-time t1 of this transient-window search
+     * for given tau, what Tcoh should the exponential window cover?
+     * for speed reasons we want to truncate Tcoh = tau * TRANSIENT_EXP_EFOLDING
+     * with the e-folding factor chosen such that the window-value
+     * is practically negligible after that, where it will be set to 0
+     */
+//     unsigned int t1 = lround( win_t0 + TRANSIENT_EXP_EFOLDING * win_tau);
+    unsigned int t1 = t0 + TRANSIENT_EXP_EFOLDING * tau;
+
+    /* compute window end-time Fstat-atom index i_t1 in [0, numAtoms) */
+    i_tmp = ( t1 - t0_data + TAtomHalf ) / TAtom  - 1; // integer round: floor(x+0.5)
+    if ( i_tmp < 0 ) {
+        i_tmp = 0;
+    }
+    unsigned int i_t1 = (unsigned int)i_tmp;
+    if ( i_t1 >= numAtoms ) {
+        i_t1 = numAtoms - 1;
+    }
+
+    /* now we have two valid atoms-indices [i_t0, i_t1]
+     * spanning our Fstat-window to sum over
+     */
+
+    float Ad    = 0.0f;
+    float Bd    = 0.0f;
+    float Cd    = 0.0f;
+    float Fa_re = 0.0f;
+    float Fa_im = 0.0f;
+    float Fb_re = 0.0f;
+    float Fb_im = 0.0f;
+
+    unsigned short input_cols = 7; // must match input matrix!
+
+    /* sum up atoms */
+    for ( unsigned int i=i_t0; i<=i_t1; i++ ) {
+
+      unsigned int t_i = t0_data + i * TAtom;
+
+      float win_i = 0.0;
+      if ( t_i >= t0 && t_i <= t1 ) {
+        float x = 1.0 * ( t_i - t0 ) / tau;
+        win_i = exp ( -x );
+      }
+
+      float win2_i = win_i * win_i;
+
+      Ad    += input[i*input_cols+0] * win2_i; // a2_alpha
+      Bd    += input[i*input_cols+1] * win2_i; // b2_alpha
+      Cd    += input[i*input_cols+2] * win2_i; // ab_alpha
+      Fa_re += input[i*input_cols+3] * win_i; // Fa_alpha_re
+      Fa_im += input[i*input_cols+4] * win_i; // Fa_alpha_im
+      Fb_re += input[i*input_cols+5] * win_i; // Fb_alpha_re
+      Fb_im += input[i*input_cols+6] * win_i; // Fb_alpha_im
+
+    }
+
+    /* get determinant */
+    float Dd = ( Ad * Bd - Cd * Cd );
+    float DdInv = 0.0f;
+    /* safety catch as in XLALWeightMultiAMCoeffs():
+     * make it so that in the end F=0 instead of -nan
+     */
+    if ( Dd > 0.0 ) {
+      DdInv  = 1.0 / Dd;
+    }
+
+    /* from XLALComputeFstatFromFaFb */
+    float F  = DdInv * (  Bd * ( Fa_re*Fa_re + Fa_im*Fa_im )
+                        + Ad * ( Fb_re*Fb_re + Fb_im*Fb_im )
+                        - 2.0 * Cd * ( Fa_re * Fb_re + Fa_im * Fb_im )
+                       );
+
+    /* store result in Fstat-matrix
+     * at unraveled index of element {m,n}
+     */
+    Fmn[outidx] = F;
+
+  } // ( (m < Fmn_rows) && (n < Fmn_cols) )
+
+} // cudaTransientFstatExpWindow()
diff --git a/pyfstat/pyCUDAkernels/cudaTransientFstatRectWindow.cu b/pyfstat/pyCUDAkernels/cudaTransientFstatRectWindow.cu
new file mode 100644
index 0000000000000000000000000000000000000000..276cc2e27cb78ae008e8d74e235675f7510a1fde
--- /dev/null
+++ b/pyfstat/pyCUDAkernels/cudaTransientFstatRectWindow.cu
@@ -0,0 +1,114 @@
+__global__ void cudaTransientFstatRectWindow ( float *input,
+                                               unsigned int numAtoms,
+                                               unsigned int TAtom,
+                                               unsigned int t0_data,
+                                               unsigned int win_t0,
+                                               unsigned int win_dt0,
+                                               unsigned int win_tau,
+                                               unsigned int win_dtau,
+                                               unsigned int N_tauRange,
+                                               float *Fmn
+                                             )
+{
+
+  /* match CUDA thread indexing and high-level (t0,tau) indexing */
+  // assume 1D block, grid setup
+  unsigned int m         = blockDim.x * blockIdx.x + threadIdx.x; // t0:  row
+
+  unsigned short input_cols = 7; // must match input matrix!
+
+  /* compute Fstat-atom index i_t0 in [0, numAtoms) */
+  unsigned int TAtomHalf = TAtom/2; // integer division
+  unsigned int t0 = win_t0 + m * win_dt0;
+  int i_tmp = ( t0 - t0_data + TAtomHalf ) / TAtom; // integer round: floor(x+0.5)
+  if ( i_tmp < 0 ) {
+    i_tmp = 0;
+  }
+  unsigned int i_t0 = (unsigned int)i_tmp;
+  if ( i_t0 >= numAtoms ) {
+    i_t0 = numAtoms - 1;
+  }
+
+  float Ad    = 0.0f;
+  float Bd    = 0.0f;
+  float Cd    = 0.0f;
+  float Fa_re = 0.0f;
+  float Fa_im = 0.0f;
+  float Fb_re = 0.0f;
+  float Fb_im = 0.0f;
+  unsigned int i_t1_last = i_t0;
+
+  /* INNER loop over timescale-parameter tau
+   * NOT parallelized so that we can still use the i_t1_last trick
+   * (empirically seems to be faster than 2D CUDA version)
+   */
+  for ( unsigned int n = 0; n < N_tauRange; n ++ ) {
+
+    if ( (m < N_tauRange) && (n < N_tauRange) ) {
+
+      /* translate n into an atoms end-index for this search interval [t0, t0+Tcoh],
+       * giving the index range of atoms to sum over
+       */
+      unsigned int tau = win_tau + n * win_dtau;
+
+      /* get end-time t1 of this transient-window search */
+      unsigned int t1 = t0 + tau;
+
+      /* compute window end-time Fstat-atom index i_t1 in [0, numAtoms) */
+      i_tmp = ( t1 - t0_data + TAtomHalf ) / TAtom  - 1; // integer round: floor(x+0.5)
+      if ( i_tmp < 0 ) {
+        i_tmp = 0;
+      }
+      unsigned int i_t1 = (unsigned int)i_tmp;
+      if ( i_t1 >= numAtoms ) {
+        i_t1 = numAtoms - 1;
+      }
+
+      /* now we have two valid atoms-indices [i_t0, i_t1]
+       * spanning our Fstat-window to sum over
+       */
+
+      for ( unsigned int i = i_t1_last; i <= i_t1; i ++ ) {
+        /* sum up atoms,
+         * special optimiziation in the rectangular-window case:
+         * just add on to previous tau values,
+         * ie re-use the sum over [i_t0, i_t1_last] from the pevious tau-loop iteration
+         */
+        Ad    += input[i*input_cols+0]; // a2_alpha
+        Bd    += input[i*input_cols+1]; // b2_alpha
+        Cd    += input[i*input_cols+2]; // ab_alpha
+        Fa_re += input[i*input_cols+3]; // Fa_alpha_re
+        Fa_im += input[i*input_cols+4]; // Fa_alpha_im
+        Fb_re += input[i*input_cols+5]; // Fb_alpha_re
+        Fb_im += input[i*input_cols+6]; // Fb_alpha_im
+        /* keep track of up to where we summed for the next iteration */
+        i_t1_last = i_t1 + 1;
+      }
+
+      /* get determinant */
+      float Dd = ( Ad * Bd - Cd * Cd );
+      float DdInv = 0.0f;
+      /* safety catch as in XLALWeightMultiAMCoeffs():
+       * make it so that in the end F=0 instead of -nan
+       */
+      if ( Dd > 0.0 ) {
+        DdInv  = 1.0 / Dd;
+      }
+
+      /* from XLALComputeFstatFromFaFb */
+      float F  = DdInv * (  Bd * ( Fa_re*Fa_re + Fa_im*Fa_im )
+                          + Ad * ( Fb_re*Fb_re + Fb_im*Fb_im )
+                          - 2.0 * Cd * ( Fa_re * Fb_re + Fa_im * Fb_im )
+                         );
+
+      /* store result in Fstat-matrix
+       * at unraveled index of element {m,n}
+       */
+      unsigned int outidx = m * N_tauRange + n;
+      Fmn[outidx] = F;
+
+    } // if ( (m < N_tauRange) && (n < N_tauRange) )
+
+  } // for ( unsigned int n = 0; n < N_tauRange; n ++ )
+
+} // cudaTransientFstatRectWindow()
diff --git a/pyfstat/tcw_fstat_map_funcs.py b/pyfstat/tcw_fstat_map_funcs.py
index 7294e0a6ced84f8776d1bafb7fad8b5766420ebd..fd43b289dd660a1ea2a13e6cfb8ac46b92f5eb7c 100644
--- a/pyfstat/tcw_fstat_map_funcs.py
+++ b/pyfstat/tcw_fstat_map_funcs.py
@@ -1,5 +1,7 @@
 """ Additional helper functions dealing with transient-CW F(t0,tau) maps """
 
+import numpy as np
+import os
 import logging
 
 # optional imports
@@ -31,15 +33,34 @@ def optional_import ( modulename, shorthand=None ):
     return success
 
 
+class pyTransientFstatMap(object):
+    '''
+    simplified object class for a F(t0,tau) F-stat map (not 2F!)
+    based on LALSuite's transientFstatMap_t type
+    replacing the gsl matrix with a numpy array
+
+    F_mn:   2D array of 2F values
+    maxF:   maximum of F (not 2F!)
+    t0_ML:  maximum likelihood transient start time t0 estimate
+    tau_ML: maximum likelihood transient duration tau estimate
+    '''
+
+    def __init__(self, N_t0Range, N_tauRange):
+        self.F_mn   = np.zeros((N_t0Range, N_tauRange), dtype=np.float32)
+        self.maxF   = float(-1.0) # Initializing to a negative value ensures that we always update at least once and hence return sane t0_d_ML, tau_d_ML even if there is only a single bin where F=0 happens.
+        self.t0_ML  = float(0.0)
+        self.tau_ML = float(0.0)
+
+
 # dictionary of the actual callable F-stat map functions we support,
 # if the corresponding modules are available.
 fstatmap_versions = {
                      'lal':    lambda multiFstatAtoms, windowRange:
                                getattr(lalpulsar,'ComputeTransientFstatMap')
                                 ( multiFstatAtoms, windowRange, False ),
-                     #'pycuda': lambda multiFstatAtoms, windowRange:
-                               #pycuda_compute_transient_fstat_map
-                                #( multiFstatAtoms, windowRange )
+                     'pycuda': lambda multiFstatAtoms, windowRange:
+                               pycuda_compute_transient_fstat_map
+                                ( multiFstatAtoms, windowRange )
                     }
 
 
@@ -51,13 +72,24 @@ def init_transient_fstat_map_features ( ):
     each key's value set to True only if
     all required modules are importable on this system.
     '''
+
     features = {}
+
     have_lal           = optional_import('lal')
     have_lalpulsar     = optional_import('lalpulsar')
     features['lal']    = have_lal and have_lalpulsar
-    features['pycuda'] = False
+
+    # import GPU features
+    have_pycuda_drv      = optional_import('pycuda.driver', 'drv')
+    have_pycuda_init     = optional_import('pycuda.autoinit', 'autoinit')
+    have_pycuda_gpuarray = optional_import('pycuda.gpuarray', 'gpuarray')
+    have_pycuda_tools    = optional_import('pycuda.tools', 'cudatools')
+    have_pycuda_compiler = optional_import('pycuda.compiler', 'cudacomp')
+    features['pycuda']   = have_pycuda_drv and have_pycuda_init and have_pycuda_gpuarray and have_pycuda_tools and have_pycuda_compiler
+
     logging.debug('Got the following features for transient F-stat maps:')
     logging.debug(features)
+
     return features
 
 
@@ -72,3 +104,222 @@ def call_compute_transient_fstat_map ( version, features, multiFstatAtoms=None,
     else:
         raise Exception('Transient F-stat map method "{}" not implemented!'.format(version))
     return FstatMap
+
+
+def reshape_FstatAtomsVector ( atomsVector ):
+    '''
+    Make a dictionary of ndarrays out of a atoms "vector" structure.
+
+    The input is a "vector"-like structure with times as the higher hierarchical
+    level and a set of "atoms" quantities defined at each timestamp.
+    The output is a dictionary with an entry for each quantity,
+    which is a 1D ndarray over timestamps for that one quantity.
+    '''
+
+    numAtoms = atomsVector.length
+    atomsDict = {}
+    atom_fieldnames = ['timestamp', 'Fa_alpha', 'Fb_alpha',
+                       'a2_alpha', 'ab_alpha', 'b2_alpha']
+    atom_dtypes     = [np.uint32, complex, complex,
+                       np.float32, np.float32, np.float32]
+    for f, field in enumerate(atom_fieldnames):
+        atomsDict[field] = np.ndarray(numAtoms,dtype=atom_dtypes[f])
+
+    for n,atom in enumerate(atomsVector.data):
+        for field in atom_fieldnames:
+            atomsDict[field][n] = atom.__getattribute__(field)
+
+    atomsDict['Fa_alpha_re'] = np.float32(atomsDict['Fa_alpha'].real)
+    atomsDict['Fa_alpha_im'] = np.float32(atomsDict['Fa_alpha'].imag)
+    atomsDict['Fb_alpha_re'] = np.float32(atomsDict['Fb_alpha'].real)
+    atomsDict['Fb_alpha_im'] = np.float32(atomsDict['Fb_alpha'].imag)
+
+    return atomsDict
+
+
+def get_absolute_kernel_path ( kernel ):
+    pyfstatdir = os.path.dirname(os.path.abspath(os.path.realpath(__file__)))
+    kernelfile = kernel + '.cu'
+    return os.path.join(pyfstatdir,'pyCUDAkernels',kernelfile)
+
+
+def pycuda_compute_transient_fstat_map ( multiFstatAtoms, windowRange ):
+    '''
+    GPU version of the function to compute transient-window "F-statistic map"
+    over start-time and timescale {t0, tau}.
+    Based on XLALComputeTransientFstatMap from LALSuite,
+    (C) 2009 Reinhard Prix, licensed under GPL
+
+    Returns a 2D matrix F_mn,
+    with m = index over start-times t0,
+    and  n = index over timescales tau,
+    in steps of dt0  in [t0,  t0+t0Band],
+    and         dtau in [tau, tau+tauBand]
+    as defined in windowRange input.
+    '''
+
+    if ( windowRange.type >= lalpulsar.TRANSIENT_LAST ):
+        raise ValueError ('Unknown window-type ({}) passed as input. Allowed are [0,{}].'.format(windowRange.type, lalpulsar.TRANSIENT_LAST-1))
+
+    # internal dict for search/setup parameters
+    tCWparams = {}
+
+    # first combine all multi-atoms
+    # into a single atoms-vector with *unique* timestamps
+    tCWparams['TAtom'] = multiFstatAtoms.data[0].TAtom
+    TAtomHalf          = int(tCWparams['TAtom']/2) # integer division
+    atoms = lalpulsar.mergeMultiFstatAtomsBinned ( multiFstatAtoms,
+                                                   tCWparams['TAtom'] )
+
+    # make a combined input matrix of all atoms vectors, for transfer to GPU
+    tCWparams['numAtoms'] = atoms.length
+    atomsDict = reshape_FstatAtomsVector(atoms)
+    atomsInputMatrix = np.column_stack ( (atomsDict['a2_alpha'],
+                                          atomsDict['b2_alpha'],
+                                          atomsDict['ab_alpha'],
+                                          atomsDict['Fa_alpha_re'],
+                                          atomsDict['Fa_alpha_im'],
+                                          atomsDict['Fb_alpha_re'],
+                                          atomsDict['Fb_alpha_im'])
+                                       )
+
+    # actual data spans [t0_data, t0_data + tCWparams['numAtoms'] * TAtom]
+    # in steps of TAtom
+    tCWparams['t0_data'] = int(atoms.data[0].timestamp)
+    tCWparams['t1_data'] = int(atoms.data[tCWparams['numAtoms']-1].timestamp + tCWparams['TAtom'])
+
+    logging.debug('t0_data={:d}, t1_data={:d}'.format(tCWparams['t0_data'],
+                                                      tCWparams['t1_data']))
+    logging.debug('numAtoms={:d}, TAtom={:d}, TAtomHalf={:d}'.format(tCWparams['numAtoms'],
+                                                                     tCWparams['TAtom'],
+                                                                     TAtomHalf))
+
+    # special treatment of window_type = none
+    # ==> replace by rectangular window spanning all the data
+    if ( windowRange.type == lalpulsar.TRANSIENT_NONE ):
+        windowRange.type    = lalpulsar.TRANSIENT_RECTANGULAR
+        windowRange.t0      = tCWparams['t0_data']
+        windowRange.t0Band  = 0
+        windowRange.dt0     = tCWparams['TAtom'] # irrelevant
+        windowRange.tau     = tCWparams['numAtoms'] * tCWparams['TAtom']
+        windowRange.tauBand = 0;
+        windowRange.dtau    = tCWparams['TAtom'] # irrelevant
+
+    """ NOTE: indices {i,j} enumerate *actual* atoms and their timestamps t_i, while the
+    * indices {m,n} enumerate the full grid of values in [t0_min, t0_max]x[Tcoh_min, Tcoh_max] in
+    * steps of deltaT. This allows us to deal with gaps in the data in a transparent way.
+    *
+    * NOTE2: we operate on the 'binned' atoms returned from XLALmergeMultiFstatAtomsBinned(),
+    * which means we can safely assume all atoms to be lined up perfectly on a 'deltaT' binned grid.
+    *
+    * The mapping used will therefore be {i,j} -> {m,n}:
+    *   m = offs_i  / deltaT		= start-time offset from t0_min measured in deltaT
+    *   n = Tcoh_ij / deltaT		= duration Tcoh_ij measured in deltaT,
+    *
+    * where
+    *   offs_i  = t_i - t0_min
+    *   Tcoh_ij = t_j - t_i + deltaT
+    *
+    """
+
+    # We allocate a matrix  {m x n} = t0Range * TcohRange elements
+    # covering the full timerange the transient window-range [t0,t0+t0Band]x[tau,tau+tauBand]
+    tCWparams['N_t0Range']  = int(np.floor( 1.0*windowRange.t0Band / windowRange.dt0 ) + 1)
+    tCWparams['N_tauRange'] = int(np.floor( 1.0*windowRange.tauBand / windowRange.dtau ) + 1)
+    FstatMap = pyTransientFstatMap ( tCWparams['N_t0Range'], tCWparams['N_tauRange'] )
+
+    logging.debug('N_t0Range={:d}, N_tauRange={:d}'.format(tCWparams['N_t0Range'],
+                                                           tCWparams['N_tauRange']))
+
+    if ( windowRange.type == lalpulsar.TRANSIENT_RECTANGULAR ):
+        FstatMap.F_mn = pycuda_compute_transient_fstat_map_rect ( atomsInputMatrix,
+                                                                  windowRange,
+                                                                  tCWparams )
+    elif ( windowRange.type == lalpulsar.TRANSIENT_EXPONENTIAL ):
+        FstatMap.F_mn = pycuda_compute_transient_fstat_map_exp ( atomsInputMatrix,
+                                                                 windowRange,
+                                                                 tCWparams )
+    else:
+        raise ValueError('Invalid transient window type {} not in [{}, {}].'.format(windowRange.type, lalpulsar.TRANSIENT_NONE, lalpulsar.TRANSIENT_LAST-1))
+
+    # out of loop: get max2F and ML estimates over the m x n matrix
+    FstatMap.maxF = FstatMap.F_mn.max()
+    maxidx = np.unravel_index ( FstatMap.F_mn.argmax(),
+                               (tCWparams['N_t0Range'],
+                                tCWparams['N_tauRange']))
+    FstatMap.t0_ML  = windowRange.t0  + maxidx[0] * windowRange.dt0
+    FstatMap.tau_ML = windowRange.tau + maxidx[1] * windowRange.dtau
+
+    logging.debug('Done computing transient F-stat map. maxF={}, t0_ML={}, tau_ML={}'.format(FstatMap.maxF , FstatMap.t0_ML, FstatMap.tau_ML))
+
+    return FstatMap
+
+
+def pycuda_compute_transient_fstat_map_rect ( atomsInputMatrix, windowRange, tCWparams ):
+    '''only GPU-parallizing outer loop, keeping partial sums with memory in kernel'''
+
+    # gpu data setup and transfer
+    logging.debug('Initial GPU memory: {}/{} MB free'.format(drv.mem_get_info()[0]/(2.**20),drv.mem_get_info()[1]/(2.**20)))
+    input_gpu = gpuarray.to_gpu ( atomsInputMatrix )
+    Fmn_gpu   = gpuarray.GPUArray ( (tCWparams['N_t0Range'],tCWparams['N_tauRange']), dtype=np.float32 )
+    logging.debug('GPU memory with input+output allocated: {}/{} MB free'.format(drv.mem_get_info()[0]/(2.**20), drv.mem_get_info()[1]/(2.**20)))
+
+    # GPU kernel
+    kernel = 'cudaTransientFstatRectWindow'
+    kernelfile = get_absolute_kernel_path ( kernel )
+    partial_Fstat_cuda_code = cudacomp.SourceModule(open(kernelfile,'r').read())
+    partial_Fstat_cuda = partial_Fstat_cuda_code.get_function(kernel)
+    partial_Fstat_cuda.prepare('PIIIIIIIIP')
+
+    # GPU grid setup
+    blockRows = min(1024,tCWparams['N_t0Range'])
+    blockCols = 1
+    gridRows  = int(np.ceil(1.0*tCWparams['N_t0Range']/blockRows))
+    gridCols  = 1
+    logging.debug('Looking to compute transient F-stat map over a N={}*{}={} (t0,tau) grid...'.format(tCWparams['N_t0Range'],tCWparams['N_tauRange'],tCWparams['N_t0Range']*tCWparams['N_tauRange']))
+
+    # running the kernel
+    logging.debug('Calling kernel with a grid of {}*{}={} blocks of {}*{}={} threads each: {} total threads...'.format(gridRows, gridCols, gridRows*gridCols, blockRows, blockCols, blockRows*blockCols, gridRows*gridCols*blockRows*blockCols))
+    partial_Fstat_cuda.prepared_call ( (gridRows,gridCols), (blockRows,blockCols,1), input_gpu.gpudata, tCWparams['numAtoms'], tCWparams['TAtom'], tCWparams['t0_data'], windowRange.t0, windowRange.dt0, windowRange.tau, windowRange.dtau, tCWparams['N_tauRange'], Fmn_gpu.gpudata )
+
+    # return results to host
+    F_mn = Fmn_gpu.get()
+
+    logging.debug('Final GPU memory: {}/{} MB free'.format(drv.mem_get_info()[0]/(2.**20),drv.mem_get_info()[1]/(2.**20)))
+
+    return F_mn
+
+
+def pycuda_compute_transient_fstat_map_exp ( atomsInputMatrix, windowRange, tCWparams ):
+    '''exponential window, inner and outer loop GPU-parallelized'''
+
+    # gpu data setup and transfer
+    logging.debug('Initial GPU memory: {}/{} MB free'.format(drv.mem_get_info()[0]/(2.**20),drv.mem_get_info()[1]/(2.**20)))
+    input_gpu = gpuarray.to_gpu ( atomsInputMatrix )
+    Fmn_gpu   = gpuarray.GPUArray ( (tCWparams['N_t0Range'],tCWparams['N_tauRange']), dtype=np.float32 )
+    logging.debug('GPU memory with input+output allocated: {}/{} MB free'.format(drv.mem_get_info()[0]/(2.**20), drv.mem_get_info()[1]/(2.**20)))
+
+    # GPU kernel
+    kernel = 'cudaTransientFstatExpWindow'
+    kernelfile = get_absolute_kernel_path ( kernel )
+    partial_Fstat_cuda_code = cudacomp.SourceModule(open(kernelfile,'r').read())
+    partial_Fstat_cuda = partial_Fstat_cuda_code.get_function(kernel)
+    partial_Fstat_cuda.prepare('PIIIIIIIIIP')
+
+    # GPU grid setup
+    blockRows = min(32,tCWparams['N_t0Range'])
+    blockCols = min(32,tCWparams['N_tauRange'])
+    gridRows  = int(np.ceil(1.0*tCWparams['N_t0Range']/blockRows))
+    gridCols  = int(np.ceil(1.0*tCWparams['N_tauRange']/blockCols))
+    logging.debug('Looking to compute transient F-stat map over a N={}*{}={} (t0,tau) grid...'.format(tCWparams['N_t0Range'], tCWparams['N_tauRange'], tCWparams['N_t0Range']*tCWparams['N_tauRange']))
+
+    # running the kernel
+    logging.debug('Calling kernel with a grid of {}*{}={} blocks of {}*{}={} threads each: {} total threads...'.format(gridRows, gridCols, gridRows*gridCols, blockRows, blockCols, blockRows*blockCols, gridRows*gridCols*blockRows*blockCols))
+    partial_Fstat_cuda.prepared_call ( (gridRows,gridCols), (blockRows,blockCols,1), input_gpu.gpudata, tCWparams['numAtoms'], tCWparams['TAtom'], tCWparams['t0_data'], windowRange.t0, windowRange.dt0, windowRange.tau, windowRange.dtau, tCWparams['N_t0Range'], tCWparams['N_tauRange'], Fmn_gpu.gpudata )
+
+    # return results to host
+    F_mn = Fmn_gpu.get()
+
+    logging.debug('Final GPU memory: {}/{} MB free'.format(drv.mem_get_info()[0]/(2.**20),drv.mem_get_info()[1]/(2.**20)))
+
+    return F_mn
diff --git a/setup.py b/setup.py
index a9d69f304d33b723a3894c2f4ab88f2adfc2f737..2f03d835110d223f056e4798043888d9b241d60d 100644
--- a/setup.py
+++ b/setup.py
@@ -7,4 +7,7 @@ setup(name='PyFstat',
       author='Gregory Ashton',
       author_email='gregory.ashton@ligo.org',
       packages=['pyfstat'],
+      include_package_data=True,
+      package_data={'pyfstat': ['pyCUDAkernels/cudaTransientFstatExpWindow.cu',
+                                'pyCUDAkernels/cudaTransientFstatRectWindow.cu']},
       )