Getting the error "ERROR: array subscript out of range" when implementing Laplace's Theorem for determinants PL/pgSQL?

Question

我正在编写一个 PL/pgSQL 函数作为练习，该函数实现拉普拉斯定理以计算行列式，然后在调用时打印解。我觉得我是这门语言的新手，找不到代码有什么问题。我认为这个想法没问题，也许有语法错误！求助！

CREATE OR REPLACE FUNCTION remove(matriz float[][], linha integer, coluna integer) RETURNS float[][] AS
$$
    DECLARE
        i integer;
        j integer;
        k integer;
        l integer;
        resultante float[][];
    BEGIN
        resultante := array_fill(0, ARRAY[array_length(matriz, 1)-1, array_length(matriz, 2)-1]);      
        k = 0;
        FOR i IN 1..array_length(matriz, 1) LOOP
            l = 0;
           FOR j IN 1..array_length(matriz, 1) LOOP
                IF j != coluna THEN
                    resultante[k][l] = matriz[i][j];
                    l = l + 1;
                END IF;
            END LOOP;

            IF i != linha THEN
                l = l + 1;
            END IF;

        END LOOP;  
        RETURN resultante;
    END;

$$ language plpgsql;

CREATE OR REPLACE FUNCTION determinant(matriz float[][], OUT produto float) AS
$$
    DECLARE
        i integer;
    BEGIN

        IF array_length(matriz, 1) <> array_length(matriz, 2) THEN
            RAISE EXCEPTION 'matrix not quadratic.';
        END IF;
        produto = 0;
        
        IF array_length(matriz, 1) = 2 THEN
            produto = matriz[1][1] * matriz[2][2] - matriz[1][2] * matriz[2][1];
        END IF;

        IF array_length(matriz, 1) > 2 THEN
            FOR i IN 1..array_length(matriz, 1) LOOP
                produto = produto + matriz[1][i] * (-1)^(0+(i-1)) * determinant(remove(matriz, 1, i));
            END LOOP;
        END IF;
    END;

$$ language plpgsql;

SELECT determinant('{{1.0,7.0, 2.0, 4.0}, {2.0, 3.0, 5.0, 4.0}, {9.0, 1.0, 8.0, 2.0}, {4.0, 1.0, 1.0, 4.0}}');

结果：

[76:1] Failed in 0 s.
[Exception, Error code 0, SQLState 2202E] ERROR: array subscript out of range
  Onde: função PL/pgSQL remove(double precision[],integer,integer) linha 15 em atribuição
função PL/pgSQL determinante(double precision[]) linha 17 em atribuição
  Line 76, column 1

Answer 1

你永远不会改变k。另一方面，你增加了 l 太多。

其中一个l = l + 1（有两个）应该是k = k + 1。

Getting the error "ERROR: array subscript out of range" when implementing Laplace's Theorem for determinants PL/pgSQL?

Getting the error "ERROR: array subscript out of range" when implementing Laplace's Theorem for determinants PL/pgSQL?

arrays

algorithm

postgresql

multidimensional-array

matrix-multiplication