## how to use culaDeviceSgels in C

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**1**of**1**### how to use culaDeviceSgels in C

Hi, I'm new in CULA and get some troubles.

1. the matrix is in col major,i want get the x where Ax=B in least square solution.A demension is m×n,so x is n×1 ,B is m×1. The problem is I copy A and B to device and set them in culaDeviceSgels , how I get x. The dimension of B is different from x. I dont know how to copy x to the host.

2.if A and B are both in row-major ,how I call the function?

1. the matrix is in col major,i want get the x where Ax=B in least square solution.A demension is m×n,so x is n×1 ,B is m×1. The problem is I copy A and B to device and set them in culaDeviceSgels , how I get x. The dimension of B is different from x. I dont know how to copy x to the host.

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`//A ,B is given,and m>=n`

float* d_A;

float* d_B;

cudaMalloc((void**)&d_A,sizeof(float)*m*n); //allocate device memory for d_A

cudaMalloc((void**)&d_B,m*sizeof(float)); //I allocate device memory for d_B

cudaMemcpy(d_A,A,sizeof(float)*m*n,cudaMemcpyHostToDevice);//copy

cudaMemcpy(d_B,B,sizeof(float)*m,cudaMemcpyHostToDevice);//copy

culaInitialize();

culaDeviceSgels('N',m,n,1,A,m,B,m);

//Then how I copy B and get x??????

cudaFree(d_A);

cudaFree(d_B);

culaShutdown();

2.if A and B are both in row-major ,how I call the function?

- sawyer
**Posts:**1**Joined:**Fri Jan 10, 2014 9:02 am

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