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Add ifftshift

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This commit is contained in:
kradchen
2023-06-08 15:24:49 +08:00
parent eca0e77fcc
commit a0db3777d2
3 changed files with 38 additions and 4 deletions
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25
src/Function2D.cpp
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@@ -837,13 +837,30 @@ Matrix Aurora::ifft_symmetric(const Matrix &aMatrix,long length)
void Aurora::fftshift(Matrix &aMatrix){ void Aurora::fftshift(Matrix &aMatrix){
int backwardLength = aMatrix.getDimSize(0)/2; int backwardLength = aMatrix.getDimSize(0)/2;
if (aMatrix.getDimSize(0)%2!=0)++backwardLength;
int forwardLength = aMatrix.getDimSize(0) - backwardLength; int forwardLength = aMatrix.getDimSize(0) - backwardLength;
double* buffer = malloc(forwardLength,true); double* buffer = malloc(forwardLength,true);
int valueStep = aMatrix.isComplex()?2:1;
for (int i = 0; i<aMatrix.getDimSize(1); ++i) { for (int i = 0; i<aMatrix.getDimSize(1); ++i) {
double* dataPtr = aMatrix.getData()+aMatrix.getDimSize(0)*i*2; double* dataPtr = aMatrix.getData()+aMatrix.getDimSize(0)*i*valueStep;
cblas_dcopy(forwardLength*2, dataPtr+backwardLength*2, 1, buffer, 1); cblas_dcopy(forwardLength*valueStep, dataPtr+backwardLength*valueStep, 1, buffer, 1);
cblas_dcopy(backwardLength*2, dataPtr, 1, dataPtr+forwardLength*2, 1); cblas_dcopy(backwardLength*valueStep, dataPtr, 1, dataPtr+forwardLength*valueStep, 1);
cblas_dcopy(forwardLength*2, buffer, 1, dataPtr, 1); cblas_dcopy(forwardLength*valueStep, buffer, 1, dataPtr, 1);
}
Aurora::free(buffer);
}
void Aurora::ifftshift(Matrix &aMatrix){
int forwardLength= aMatrix.getDimSize(0)/2;
if (aMatrix.getDimSize(0)%2!=0)++forwardLength;
int backwardLength = aMatrix.getDimSize(0) - forwardLength;
double* buffer = malloc(forwardLength,true);
int valueStep = aMatrix.isComplex()?2:1;
for (int i = 0; i<aMatrix.getDimSize(1); ++i) {
double* dataPtr = aMatrix.getData()+aMatrix.getDimSize(0)*i*valueStep;
cblas_dcopy(forwardLength*valueStep, dataPtr+backwardLength*valueStep, 1, buffer, 1);
cblas_dcopy(backwardLength*valueStep, dataPtr, 1, dataPtr+forwardLength*valueStep, 1);
cblas_dcopy(forwardLength*valueStep, buffer, 1, dataPtr, 1);
} }
Aurora::free(buffer); Aurora::free(buffer);
} }

6
src/Function2D.h
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@@ -135,6 +135,12 @@ namespace Aurora
*/ */
void fftshift(Matrix &aMatrix); void fftshift(Matrix &aMatrix);
/**
* fftshift,在原有数据上进行修改，将fft的数据的前半部分和后半部分交换，支持2D数据
* @param aMatrix
*/
void ifftshift(Matrix &aMatrix);
/** /**
* 逆fft，支持到2维，输入必须是复数，输出必是复数 * 逆fft，支持到2维，输入必须是复数，输出必是复数
* @attention 如有需要可使用real去除虚部 * @attention 如有需要可使用real去除虚部

11
test/Function2D_Test.cpp
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@@ -369,6 +369,17 @@ TEST_F(Function2D_Test, fftAndComplexAndIfft){
EXPECT_DOUBLE_EQ(-3.4641, fourDecimalRound(result3[4].imag())); EXPECT_DOUBLE_EQ(-3.4641, fourDecimalRound(result3[4].imag()));
EXPECT_DOUBLE_EQ(-1.0, fourDecimalRound(result3[13].real())); EXPECT_DOUBLE_EQ(-1.0, fourDecimalRound(result3[13].real()));
EXPECT_DOUBLE_EQ(-3.4641, fourDecimalRound(result3[16].imag())); EXPECT_DOUBLE_EQ(-3.4641, fourDecimalRound(result3[16].imag()));
{
auto fm = Aurora::Matrix::fromRawData(new double[7]{1,2,3, 4, 5, 6, 7},7,1);
Aurora::fftshift(fm);
EXPECT_DOUBLE_EQ(5, fm[0]);
EXPECT_DOUBLE_EQ(1, fm[3]);
EXPECT_DOUBLE_EQ(4, fm[6]);
Aurora::ifftshift(fm);
EXPECT_DOUBLE_EQ(1, fm[0]);
EXPECT_DOUBLE_EQ(4, fm[3]);
EXPECT_DOUBLE_EQ(7, fm[6]);
}
} }
TEST_F(Function2D_Test, hilbert) { TEST_F(Function2D_Test, hilbert) {