Make and use a separate zconvolve method without scaling

When you're doing hundreds or thousands of separate zconvolve calls into the
same buffer, it's more efficient to do the multiply once at the end instead of
in each call.

1 files changed, 13 insertions, 3 deletions

diff --git a/common/pffft.h b/common/pffft.h
index 3b402ca4..4bc3ebb6 100644
--- a/common/pffft.h
+++ b/common/pffft.h
@@ -152,8 +152,8 @@ void pffft_transform_ordered(PFFFT_Setup *setup, const float *input, float *outp
 void pffft_zreorder(PFFFT_Setup *setup, const float *input, float *output, pffft_direction_t direction);
 
 /**
- * Perform a multiplication of the z-domain data in dft_a and dft_b and
- * accumulate them into dft_ab. The arrays should have been obtained with
+ * Perform a multiplication of the z-domain data in dft_a and dft_b, and scale
+ * and accumulate into dft_ab. The arrays should have been obtained with
  * pffft_transform(..., PFFFT_FORWARD) or pffft_zreorder(..., PFFFT_BACKWARD)
  * and should *not* be in the usual order (otherwise just perform the operation
  * yourself as the dft coeffs are stored as interleaved complex numbers).
@@ -162,7 +162,17 @@ void pffft_zreorder(PFFFT_Setup *setup, const float *input, float *output, pffft
  *
  * The dft_a, dft_b, and dft_ab parameters may alias.
  */
-void pffft_zconvolve_accumulate(PFFFT_Setup *setup, const float *dft_a, const float *dft_b, float *dft_ab, float scaling);
+void pffft_zconvolve_scale_accumulate(PFFFT_Setup *setup, const float *dft_a, const float *dft_b, float *dft_ab, float scaling);
+
+/**
+ * Perform a multiplication of the z-domain data in dft_a and dft_b, and
+ * accumulate into dft_ab.
+ *
+ * The operation performed is: dft_ab += dft_a * dft_b
+ *
+ * The dft_a, dft_b, and dft_ab parameters may alias.
+ */
+void pffft_zconvolve_accumulate(PFFFT_Setup *setup, const float *dft_a, const float *dft_b, float *dft_ab);
 
 /**
  * The float buffers must have the correct alignment (16-byte boundary on intel