From 9c5a4b48d1edf808aa754b7c5b73c728e5f0d5e0 Mon Sep 17 00:00:00 2001
From: Heinz-Bernd Eggenstein <heinz-bernd.eggenstein@aei.mpg.de>
Date: Fri, 21 Sep 2012 17:00:39 +0200
Subject: [PATCH] added comments in header file for extended plan generation
function
---
include/clFFT.h | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/include/clFFT.h b/include/clFFT.h
index 9deb2ca..e1f46aa 100644
--- a/include/clFFT.h
+++ b/include/clFFT.h
@@ -98,6 +98,25 @@ typedef enum
clFFT_InterleavedComplexFormat = 1
}clFFT_DataFormat;
+// enum for twiddle factor method selection (essentially different methods to evaluate
+// sin(x) and cos(x) on a grid x_k= 2*pi*k/N for some N, k=0..N-1 )
+//
+// clFFT_native_trig : the original method, using native_sin, native_cos
+// : NOTE: precision is hardware dependent, see OpenCL 1.1 spec
+// clFFT_sincosfunc : alternative method using sincos function (slow in most
+// : implementations, accuracy as defined in OpenCL 1.1 spec
+// clFFT_BigLUT : alternative version using Lookup tables stored as part of the
+// : plan. The LUTs size grow with O(sqrt(N)) , where N is the
+// : total size of the transform (over all dimensions). This should
+// : be the most accurate option and have much better performance than
+// : with option clFFT_sincosfunc
+// clFFT_TaylorLUT : alternative method using a constant size Look-Up-Table and Taylor
+// : series approx of sin,cos
+// clFFT_RFU{n} : reserved for future use, so that clFFT_TwiddleFactorMethod may use
+// : the lower 3 bits of the flags argument to clFFT_CreatePlanAdv.
+// : All options are mutually exclusive.
+
+
typedef enum
{
clFFT_native_trig = 0,
@@ -133,6 +152,27 @@ typedef void* clFFT_Plan;
clFFT_Plan clFFT_CreatePlan( cl_context context, clFFT_Dim3 n, clFFT_Dimension dim, clFFT_DataFormat dataFormat, cl_int *error_code );
+/**
+ * Extended plan constructor, allows to specify plan options in the flags parameter.
+ * Currently only values of the enumeration clFFT_TwiddleFactorMethod are supported to
+ * choose the method for twiddle factor computations.
+ *
+ * Param:
+ * context : cl_context to use
+ * n : transform lengths in (up to) 3 dimensions
+ * dim : dimension of the transform
+ * dataFormat: see clFFT_DataFormat type
+ * flags : plan generation options. Use OR to specify more than one option
+ * (currently only the mutually exclusive enumeration values of
+ * clFFT_TwiddleFactorMethod are supported)
+ * error_code: pointer to error code, in case of error
+ *
+ * Returns:
+ * freshly allocated clFFT_Plan object holding the plan for the specified transform.
+ * Can be reused for several FFT plan executions.
+ * The caller is responsible to deallocate this object after use.
+ */
+
clFFT_Plan clFFT_CreatePlanAdv( cl_context context, clFFT_Dim3 n, clFFT_Dimension dim, clFFT_DataFormat dataFormat, unsigned long flags, cl_int *error_code );
void clFFT_DestroyPlan( clFFT_Plan plan );
--
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