1 /* ----------------------------------------------------------------------
2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
4 * $Date: 17. January 2013
7 * Project: CMSIS DSP Library
8 * Title: arm_mat_scale_f32.c
10 * Description: Multiplies a floating-point matrix by a scalar.
12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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15 * modification, are permitted provided that the following conditions
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27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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39 * -------------------------------------------------------------------- */
44 * @ingroup groupMatrix
48 * @defgroup MatrixScale Matrix Scale
50 * Multiplies a matrix by a scalar. This is accomplished by multiplying each element in the
51 * matrix by the scalar. For example:
52 * \image html MatrixScale.gif "Matrix Scaling of a 3 x 3 matrix"
54 * The function checks to make sure that the input and output matrices are of the same size.
56 * In the fixed-point Q15 and Q31 functions, <code>scale</code> is represented by
57 * a fractional multiplication <code>scaleFract</code> and an arithmetic shift <code>shift</code>.
58 * The shift allows the gain of the scaling operation to exceed 1.0.
59 * The overall scale factor applied to the fixed-point data is
61 * scale = scaleFract * 2^shift.
66 * @addtogroup MatrixScale
71 * @brief Floating-point matrix scaling.
72 * @param[in] *pSrc points to input matrix structure
73 * @param[in] scale scale factor to be applied
74 * @param[out] *pDst points to output matrix structure
75 * @return The function returns either <code>ARM_MATH_SIZE_MISMATCH</code>
76 * or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
80 arm_status arm_mat_scale_f32(
81 const arm_matrix_instance_f32 * pSrc,
83 arm_matrix_instance_f32 * pDst)
85 float32_t *pIn = pSrc->pData; /* input data matrix pointer */
86 float32_t *pOut = pDst->pData; /* output data matrix pointer */
87 uint32_t numSamples; /* total number of elements in the matrix */
88 uint32_t blkCnt; /* loop counters */
89 arm_status status; /* status of matrix scaling */
91 #ifndef ARM_MATH_CM0_FAMILY
93 float32_t in1, in2, in3, in4; /* temporary variables */
94 float32_t out1, out2, out3, out4; /* temporary variables */
96 #endif // #ifndef ARM_MATH_CM0_FAMILY
98 #ifdef ARM_MATH_MATRIX_CHECK
99 /* Check for matrix mismatch condition */
100 if((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols))
102 /* Set status as ARM_MATH_SIZE_MISMATCH */
103 status = ARM_MATH_SIZE_MISMATCH;
106 #endif /* #ifdef ARM_MATH_MATRIX_CHECK */
108 /* Total number of samples in the input matrix */
109 numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;
111 #ifndef ARM_MATH_CM0_FAMILY
113 /* Run the below code for Cortex-M4 and Cortex-M3 */
116 blkCnt = numSamples >> 2;
118 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
119 ** a second loop below computes the remaining 1 to 3 samples. */
122 /* C(m,n) = A(m,n) * scale */
123 /* Scaling and results are stored in the destination buffer. */
140 /* update pointers to process next sampels */
144 /* Decrement the numSamples loop counter */
148 /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
149 ** No loop unrolling is used. */
150 blkCnt = numSamples % 0x4u;
154 /* Run the below code for Cortex-M0 */
156 /* Initialize blkCnt with number of samples */
159 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
163 /* C(m,n) = A(m,n) * scale */
164 /* The results are stored in the destination buffer. */
165 *pOut++ = (*pIn++) * scale;
167 /* Decrement the loop counter */
171 /* Set status as ARM_MATH_SUCCESS */
172 status = ARM_MATH_SUCCESS;
175 /* Return to application */
180 * @} end of MatrixScale group