TheAlgorithms/Python · error · Exception

change_component: indices out of bounds

Error message

change_component: indices out of bounds

What it means

Raised by Matrix.component(x, y) in linear_algebra/src/lib.py:372 when the requested cell lies outside 0 <= x < height, 0 <= y < width. The message text 'change_component: indices out of bounds' is misleading — this is the getter, and the message was copy-pasted from the setter — but the cause is simply an out-of-bounds (x, y) pair. Indices here are 0-based and negative indices are NOT supported (unlike Vector.component).

Source

Thrown at linear_algebra/src/lib.py:372

        """
        getter for the height
        """
        return self.__height

    def width(self) -> int:
        """
        getter for the width
        """
        return self.__width

    def component(self, x: int, y: int) -> float:
        """
        returns the specified (x,y) component
        """
        if 0 <= x < self.__height and 0 <= y < self.__width:
            return self.__matrix[x][y]
        else:
            raise Exception("change_component: indices out of bounds")

    def change_component(self, x: int, y: int, value: float) -> None:
        """
        changes the x-y component of this matrix
        """
        if 0 <= x < self.__height and 0 <= y < self.__width:
            self.__matrix[x][y] = value
        else:
            raise Exception("change_component: indices out of bounds")

    def minor(self, x: int, y: int) -> float:
        """
        returns the minor along (x, y)
        """
        if self.__height != self.__width:
            raise Exception("Matrix is not square")
        minor = self.__matrix[:x] + self.__matrix[x + 1 :]
        for i in range(len(minor)):

View on GitHub (pinned to f5988cc097)

Solutions

1. Clamp the indices or bounds-check 0 <= x < m.height() and 0 <= y < m.width() before calling.
2. Convert 1-based indices: x0, y0 = x - 1, y - 1.
3. Fix loop ranges to range(m.height()) / range(m.width()).
4. Do not use negative indices with this API — wrap them first: x % m.height().

Example fix

// before
val = m.component(2, 2)  # on a 2x2 matrix: Exception

// after
if 0 <= x < m.height() and 0 <= y < m.width():
    val = m.component(x, y)
else:
    raise IndexError(f"({x}, {y}) outside {m.height()}x{m.width()}")

def in_bounds(m, x: int, y: int) -> bool:
    return 0 <= x < m.height() and 0 <= y < m.width()

if not in_bounds(m, x, y):
    raise IndexError(f"({x}, {y}) outside {m.height()}x{m.width()}")
value = m.component(x, y)

def is_valid_cell(m, x, y) -> bool:
    return (
        isinstance(x, int) and isinstance(y, int)
        and 0 <= x < m.height() and 0 <= y < m.width()
    )

try:
    value = m.component(x, y)
except Exception as e:
    if "indices out of bounds" in str(e):
        raise IndexError(f"cell ({x},{y}) outside {m.height()}x{m.width()}") from e
    raise

When it happens

Trigger: Calling m.component(2, 0) on a 2x2 matrix, or using 1-based indices from a spec/paper directly (m.component(1, 1) is the top-left cell, not the second row/col), or negative indices like m.component(-1, -1) which the 0 <= x check rejects.

Common situations: Translating 1-based mathematical notation into code, off-by-one loop bounds, or indices coming from another system that uses negative indexing.

Related errors

• index out of range
• Indices out of bounds
• determinant modular {req_l} of encryption key({det}) is not
• 'table' has to be of square shaped array but got a {rows}x{c
• matrix must have the same dimension!

AI-assisted analysis of TheAlgorithms/Python@f5988cc097 (2026-08-14). Data as JSON: /api/errors/0a13fe38c1d8123f. Report an issue: GitHub.