Add fftshift ,fft with size ,and their test.

src/Function2D.cpp

@@ -578,23 +578,34 @@ Matrix Aurora::median(const Matrix &aMatrix) {
     }
 }
 
-Matrix Aurora::fft(const Matrix &aMatrix) {
+Matrix Aurora::fft(const Matrix &aMatrix, long aFFTSize) {
     double *output = nullptr;
     mkl_free_buffers();
-    output = malloc(aMatrix.getDataSize(), true);
+    MKL_LONG rowSize = (aFFTSize>0)?aFFTSize:aMatrix.getDimSize(0);
+    //实际需要copy赋值的非0值
+    MKL_LONG needCopySize = (rowSize<aMatrix.getDimSize(0))?rowSize:aMatrix.getDimSize(0);
+    MKL_LONG bufferSize = rowSize*aMatrix.getDimSize(1);
+    output = malloc(bufferSize, true);
+    double zero = 0.0;
+    //先全部置为0
+    cblas_dcopy(bufferSize*2, &zero, 0, output, 1);
     if (!aMatrix.isComplex()) {
-        cblas_dcopy(aMatrix.getDataSize(), aMatrix.getData(), 1, output, 2);
+        //按列copy原值
-        double zero = 0.0;
+        for (int i = 0 ; i < aMatrix.getDimSize(1); ++i) {
-        cblas_dcopy(aMatrix.getDataSize(), &zero, 0, output+1, 2);
+            cblas_dcopy(needCopySize, aMatrix.getData()+i*aMatrix.getDimSize(0), 1, output+i*rowSize*2, 2);
+        }
     } else {
-        cblas_zcopy(aMatrix.getDataSize(), aMatrix.getData(), 1, output, 1);
+        //按列copy原值
+        for (int i = 0 ; i < aMatrix.getDimSize(1); ++i) {
+            cblas_zcopy(needCopySize, aMatrix.getData()+i*aMatrix.getDimSize(0)*2, 1, output+i*rowSize*2, 1);
+        }
     }
 
     DFTI_DESCRIPTOR_HANDLE my_desc_handle = NULL;
     MKL_LONG status;
 
     //创建 Descriptor, 精度 double , 输入类型实数, 维度1
-    status = DftiCreateDescriptor(&my_desc_handle, DFTI_DOUBLE, DFTI_COMPLEX, 1, aMatrix.getDimSize(0));
+    status = DftiCreateDescriptor(&my_desc_handle, DFTI_DOUBLE, DFTI_COMPLEX, 1, rowSize);
     if (status != DFTI_NO_ERROR) goto error;
 
     //通过 setValue 配置Descriptor
@@ -603,11 +614,11 @@ Matrix Aurora::fft(const Matrix &aMatrix) {
     if (status != DFTI_NO_ERROR) goto error;
 
     //每个傅里叶变换的输入距离
-    status = DftiSetValue(my_desc_handle,DFTI_INPUT_DISTANCE,aMatrix.getDimSize(0));
+    status = DftiSetValue(my_desc_handle,DFTI_INPUT_DISTANCE,rowSize);
     if (status != DFTI_NO_ERROR) goto error;
 
     //每个傅里叶变换的输出距离
-    status = DftiSetValue(my_desc_handle,DFTI_OUTPUT_DISTANCE,aMatrix.getDimSize(0));
+    status = DftiSetValue(my_desc_handle,DFTI_OUTPUT_DISTANCE,rowSize);
     if (status != DFTI_NO_ERROR) goto error;
 
     //傅里叶变换的数量
@@ -626,7 +637,7 @@ Matrix Aurora::fft(const Matrix &aMatrix) {
     status = DftiFreeDescriptor(&my_desc_handle);
     if (status != DFTI_NO_ERROR) goto error;
     mkl_free_buffers();
-    return Matrix::New(output, aMatrix.getDimSize(0), aMatrix.getDimSize(1), aMatrix.getDimSize(2), Complex);
+    return Matrix::New(output, rowSize, aMatrix.getDimSize(1), aMatrix.getDimSize(2), Complex);
     error:
         std::cerr<<"FFT fail, error message:"<<DftiErrorMessage(status)<<std::endl;
         return Matrix();
@@ -710,6 +721,19 @@ Matrix Aurora::ifft_symmetric(const Matrix &aMatrix,long length)
     return real(ifft(Matrix::New(calcData,length,1,1,Complex)));
 }
 
+void Aurora::fftshift(Matrix &aMatrix){
+    int backwardLength = aMatrix.getDimSize(0)/2;
+    int forwardLength = aMatrix.getDimSize(0) - backwardLength;
+    double* buffer = malloc(forwardLength,true);
+    for (int i = 0; i<aMatrix.getDimSize(1); ++i) {
+        double* dataPtr = aMatrix.getData()+aMatrix.getDimSize(0)*i*2;
+        cblas_dcopy(forwardLength*2, dataPtr+backwardLength*2, 1, buffer, 1);
+        cblas_dcopy(backwardLength*2, dataPtr, 1, dataPtr+forwardLength*2, 1);
+        cblas_dcopy(forwardLength*2, buffer, 1, dataPtr, 1);
+    }
+    Aurora::free(buffer);
+}
+
 Matrix Aurora::hilbert(const Matrix &aMatrix) {
     auto x = fft(aMatrix);
     auto h = malloc(aMatrix.getDimSize(0));

src/Function2D.h

@@ -103,9 +103,16 @@ namespace Aurora
     /**
      * FFT,支持到2维，输入可以是常数可以是复数，输出必是复数
      * @param aMatrix 目标矩阵
+     * @param aFFTSize 目标矩阵需要处理的长度，默认为-1即全部
      * @return fft后的复数矩阵
      */
-    Matrix fft(const Matrix &aMatrix);
+    Matrix fft(const Matrix &aMatrix, long aFFTSize = -1);
+
+    /**
+    * 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 fftshift(Matrix &aMatrix);
 
     /**
      * 逆fft，支持到2维，输入必须是复数，输出必是复数

test/Function2D_Test.cpp

@@ -334,8 +334,8 @@ TEST_F(Function2D_Test, median) {
 TEST_F(Function2D_Test, fftAndComplexAndIfft){
     double *input =  new double[20]{1,1,0,2,2,0,1,1,0,2,1,1,0,2,2,0,1,1,0,2};
     auto ma = Aurora::Matrix::fromRawData(input,10,2);
-    auto ret = Aurora::fft(ma);
+    auto fftrett = Aurora::fft(ma);
-    std::complex<double>* result = (std::complex<double>*)ret.getData();
+    std::complex<double>* result = (std::complex<double>*)fftrett.getData();
     //检验fft结果与matlab是否对应
     EXPECT_DOUBLE_EQ(0.0729, fourDecimalRound(result[1].real()));
     EXPECT_DOUBLE_EQ(2.4899, fourDecimalRound(result[2].imag()));
@@ -344,12 +344,33 @@ TEST_F(Function2D_Test, fftAndComplexAndIfft){
     //检验fft的结果是否共轭
     EXPECT_DOUBLE_EQ(0, result[4].imag()+result[6].imag());
     EXPECT_DOUBLE_EQ(0, result[4].real()-result[6].real());
-    ret= Aurora::ifft(ret);
+    auto ret= Aurora::ifft(fftrett);
     std::complex<double>* ifftResult = (std::complex<double>*)ret.getData();
     EXPECT_DOUBLE_EQ(fourDecimalRound(ifftResult[1].real()),1.0);
     EXPECT_DOUBLE_EQ(fourDecimalRound(ifftResult[3].real()),2.0);
     EXPECT_DOUBLE_EQ(fourDecimalRound(ifftResult[11].real()),1.0);
     EXPECT_DOUBLE_EQ(fourDecimalRound(ifftResult[13].real()),2.0);
+    Aurora::fftshift(fftrett);
+    EXPECT_DOUBLE_EQ(0.0729, fourDecimalRound(result[6].real()));
+    EXPECT_DOUBLE_EQ(2.4899, fourDecimalRound(result[7].imag()));
+    EXPECT_DOUBLE_EQ(-2., fourDecimalRound(result[10].real()));
+    EXPECT_DOUBLE_EQ(-0.2245, fourDecimalRound(result[11].imag()));
+
+    auto fftrett2 = Aurora::fft(ma,5);
+    auto result2 = (std::complex<double>*)fftrett2.getData();
+    //检验fft结果与matlab是否对应
+    EXPECT_DOUBLE_EQ(0.3090, fourDecimalRound(result2[1].real()));
+    EXPECT_DOUBLE_EQ(-1.3143, fourDecimalRound(result2[2].imag()));
+    EXPECT_DOUBLE_EQ(-0.8090, fourDecimalRound(result2[7].real()));
+    EXPECT_DOUBLE_EQ(1.3143, fourDecimalRound(result2[8].imag()));
+
+    auto fftrett3 = Aurora::fft(ma,12);
+    auto result3 = (std::complex<double>*)fftrett3.getData();
+    //检验fft结果与matlab是否对应
+    EXPECT_DOUBLE_EQ(-1.0, fourDecimalRound(result3[1].real()));
+    EXPECT_DOUBLE_EQ(-3.4641, fourDecimalRound(result3[4].imag()));
+    EXPECT_DOUBLE_EQ(-1.0, fourDecimalRound(result3[13].real()));
+    EXPECT_DOUBLE_EQ(-3.4641, fourDecimalRound(result3[16].imag()));
 }
 
 TEST_F(Function2D_Test, hilbert) {