added simple fft

lib/simple_fft/error_handling.hpp

@@ -0,0 +1,57 @@
+#ifndef __SIMPLE_FFT__ERROR_HANDLING_HPP
+#define __SIMPLE_FFT__ERROR_HANDLING_HPP
+
+namespace simple_fft {
+namespace error_handling {
+
+enum EC_SimpleFFT
+{
+    EC_SUCCESS = 0,
+    EC_UNSUPPORTED_DIMENSIONALITY,
+    EC_WRONG_FFT_DIRECTION,
+    EC_ONE_OF_DIMS_ISNT_POWER_OF_TWO,
+    EC_NUM_OF_ELEMS_IS_ZERO,
+    EC_WRONG_CHECK_FFT_MODE,
+    EC_RELATIVE_ERROR_TOO_LARGE
+};
+
+inline void GetErrorDescription(const EC_SimpleFFT error_code,
+                                const char *& error_description)
+{
+    switch(error_code)
+    {
+    case EC_SUCCESS:
+        error_description = "Calculation was successful!";
+        break;
+    case EC_UNSUPPORTED_DIMENSIONALITY:
+        error_description = "Unsupported dimensionality: currently only 1D, 2D "
+                            "and 3D arrays are supported";
+        break;
+    case EC_WRONG_FFT_DIRECTION:
+        error_description = "Wrong direction for FFT was specified";
+        break;
+    case EC_ONE_OF_DIMS_ISNT_POWER_OF_TWO:
+        error_description = "Unsupported dimensionality: one of dimensions is not "
+                            "a power of 2";
+        break;
+    case EC_NUM_OF_ELEMS_IS_ZERO:
+        error_description = "Number of elements for FFT or IFFT is zero!";
+        break;
+    case EC_WRONG_CHECK_FFT_MODE:
+        error_description = "Wrong check FFT mode was specified (should be either "
+                            "Parseval theorem or energy conservation check";
+        break;
+    case EC_RELATIVE_ERROR_TOO_LARGE:
+        error_description = "Relative error returned by FFT test exceeds specified "
+                            "relative tolerance";
+        break;
+    default:
+        error_description = "Unknown error";
+        break;
+    }
+}
+
+} // namespace error_handling
+} // namespace simple_fft
+
+#endif // __SIMPLE_FFT__ERROR_HANDLING_HPP