什麼是GSL BLAS函數所需的「const gsl_vector_float」？

Question

我正在嘗試使用GSL來計算兩個向量之間的點積。矢量是矩陣列的視圖。我調用gsl_blas_dsdot(&view1.vector, &view2.vector, &val)這樣的函數，但在編譯時，我收到警告，說明函數預期的參數類型const gsl_vector_float *，並且我得到一個無意義的結果。這裏是一個代碼來說明：

#include<stdio.h> 
#include<gsl/gsl_matrix.h> 
#include<gsl/gsl_vector.h> 
#include<gsl/gsl_blas.h> 

void main(void){ 
    int i; 
    double val = 111.111; // Initialize to something 
    gsl_matrix *A = gsl_matrix_alloc(3,3); //Initialize mx 
    gsl_matrix_set_identity(A); // Set mx to identity 
    gsl_matrix_set(A,0,1,3.14); 
    gsl_vector_view a1 = gsl_matrix_column(A,0); // Vector allocations 
    gsl_vector_view a2 = gsl_matrix_column(A,1); 
    /* Print the vectors */ 
    printf("a1 = "); 
    for(i=0; i<3; i++){ 
    printf("%g ", gsl_vector_get(&a1.vector,i));} 
    printf("\na2 = "); 
    for(i=0; i<3; i++){ 
    printf("%g ", gsl_vector_get(&a2.vector,i));} 
    printf("\n"); 
    gsl_blas_dsdot(&a1.vector, &a2.vector, &val); // Dot product 
    printf("a1.a2 = %.2f\n", val); // Print result 
} 

我用gcc版本5.4.0編譯，GSL版本2.2.1，與以下內容：

gcc example.c -o example -lgsl -lgslcblas

而且我得到以下警告和雖然程序執行，其結果是荒謬的：

gsl_dot.c: In function ‘main’: 
gsl_dot.c:22:18: warning: passing argument 1 of ‘gsl_blas_dsdot’ from incompatible pointer type [-Wincompatible-pointer-types] 
    gsl_blas_dsdot(&a1.vector, &a2.vector, &val); // Dot product 
       ^
In file included from gsl_dot.c:4:0: 
/usr/local/include/gsl/gsl_blas.h:56:5: note: expected ‘const gsl_vector_float * {aka const struct <anonymous> *}’ but argument is of type ‘gsl_vector * {aka struct <anonymous> *}’ 
int gsl_blas_dsdot (const gsl_vector_float * X, 
    ^
gsl_dot.c:22:30: warning: passing argument 2 of ‘gsl_blas_dsdot’ from incompatible pointer type [-Wincompatible-pointer-types] 
    gsl_blas_dsdot(&a1.vector, &a2.vector, &val); // Dot product 
          ^
In file included from gsl_dot.c:4:0: 
/usr/local/include/gsl/gsl_blas.h:56:5: note: expected ‘const gsl_vector_float * {aka const struct <anonymous> *}’ but argument is of type ‘gsl_vector * {aka struct <anonymous> *}’ 
int gsl_blas_dsdot (const gsl_vector_float * 

還要注意的是複製矩陣列到gsl_vector類型使用get_matrix_get_col()會導致相同的警告。

任何人都可以請協助嗎？這些gsl矢量和矢量視圖是什麼使它們成爲不兼容的類型？這些const gsl_vector_float類型是什麼？

Answer 1

我仍然不知道const gsl_vector_float是什麼，但我確實發現使用函數gsl_blas_ddot而不是gsl_blas_dsdot編譯時沒有警告並且無法正確執行。

According to the documentation，我希望給出更多的細節，gsl_blas_ddot需要const gsl_vector *作爲參數。這顯然不同於所討論的const gsl_vector_float *。