使用 BLAS 将实数矩阵与复数向量相乘 [英] Multiplying real matrix with a complex vector using BLAS

问题描述

如何使用 Blas 将实矩阵与复向量相乘?当我使用 ccsrgemv() 之类的函数时，会出现类型不匹配错误?

How can I use Blas to multiply a real matrix with a complex vector ? When I use functions like ccsrgemv() I get type mismatch errors?

error: argument of type "float *" is incompatible with parameter of type "std::complex<float> *"

推荐答案

使用两个矩阵向量乘法 (A * (x + iy) = A * x + i A * y).更准确地说，将您的复向量视为步长为 2 的两个纠缠实向量.BLAS 可让您做到这一点.

Use two matrix-vector multiplications (A * (x + iy) = A * x + i A * y). More precisely, consider your complex vector as two entangled real vectors with stride 2. BLAS lets you do this.

更新:实际上，我没有注意到你在做 Sparse BLAS.对于 dgemv 我的技巧有效，但对于 csrgemv 则无效.恐怕你必须分别维护实部和虚部.

UPDATE: actually, I did not notice that you were doing Sparse BLAS. For dgemv my trick works, but for csrgemv it doesn't. I'm afraid you have to maintain real and imaginary part separately.

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