Add fft_c2r numpy based implementation for unittest. (PaddlePaddle#34)

* add fft_c2r numpy implementation
KPatr1ck · Sep 10, 2021 · fcd9069 · fcd9069
1 parent 3765c70
commit fcd9069
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Showing 2 changed files with 11 additions and 4 deletions.
diff --git a/paddle/fluid/operators/spectral_op.cc b/paddle/fluid/operators/spectral_op.cc
@@ -51,7 +51,7 @@ class FFTC2COpMaker : public framework::OpProtoAndCheckerMaker {
                          "fft_norm_type, the fft normalization type.");
     AddAttr<bool>("forward", "bool, the fft direction.");
     AddComment(R"DOC(
-      // add doc here
+      Compute complex to complex FFT.
     )DOC");
   }
 };
@@ -135,7 +135,7 @@ class FFTR2COpMaker : public framework::OpProtoAndCheckerMaker {
     AddAttr<bool>("forward", "bool, the fft direction.");
     AddAttr<bool>("onesided", "bool, perform onesided fft.");
     AddComment(R"DOC(
-      // add doc here
+      Compute real to complex FFT.
     )DOC");
   }
 };
@@ -236,7 +236,7 @@ class FFTC2ROpMaker : public framework::OpProtoAndCheckerMaker {
         "specified by axis.")
         .SetDefault(0L);
     AddComment(R"DOC(
-      // add doc here
+      Compute complex to complex FFT.
     )DOC");
   }
 };

diff --git a/python/paddle/fluid/tests/unittests/fft/spectral_op_np.py b/python/paddle/fluid/tests/unittests/fft/spectral_op_np.py
@@ -98,4 +98,11 @@ def fft_r2c_backward(dy, x, axes, normalization, forward, onesided):
 
 
 def fft_c2r(x, axes, normalization, forward, last_dim_size):
-    pass
+    a = asarray(x)
+    s, axes = _cook_nd_args(a, axes=axes, invreal=1)
+    if last_dim_size is not None:
+        s[-1] = last_dim_size
+    for ii in range(len(axes) - 1):
+        a = _fftc2c(a, s[ii], axes[ii], normalization, forward)
+    a = _fftc2r(a, s[-1], axes[-1], normalization, forward)
+    return a