8.6.20. MQuadExpr¶

class MQuadExpr¶

Represents a multidimensional array consisting of QuadExprs. Generally, It is generated by arithmetic operations among constant, Var, MVar, LinExpr, QuadExpr and other types. For example:

# multidimensional array linear expression multiplied by a variable
mLinExpr * x
# matrix multiplication of two multidimensional array variables
mvar1 @ mvar2

Properties

`ndim`	Number of MQuadExpr dimensions
`shape`	Shape of the MQuadExpr
`size`	Number of expressions contained in the QuadExpr

ndim¶: Number of MQuadExpr dimensions

shape¶: Shape of the MQuadExpr

size¶: Number of expressions contained in the QuadExpr

Methods

`zeros()`	Return a MQuadExpr of the specified shape containing empty expressions
`clear()`	Perform the clear operation on all contained quadratic expressions, that is, all contained quadratic expressions become empty expressions
`copy()`	Return a copy of the MQuadExpr
`getValue()`	After the problem is solved, the values of all quadratic expressions are returned
`item()`	Get the unique expression contained in the current MQuadExpr
`sum()`	Sum all included expressions and return the summed result

static zeros(shape)

Return a MQuadExpr of the specified shape containing empty expressions

Parameters: shape – The shape to be specified.

example:

mQuadExpr = MQuadExpr.zeros((2, 2))
mQuadExpr += x * x
print(mQuadExpr[0, 0].item().size() == 1)

clear()¶

Perform the clear operation on all contained quadratic expressions, that is, all contained quadratic expressions become empty expressions.

example:

mQuadExpr.clear()
print(mQuadExpr[0, 0].item().size() == 0)

copy()¶

Return a copy of the MQuadExpr.

example:

another = mQuadExpr.copy()

getValue()¶

After the problem is solved, the values of all quadratic expressions are returned.

example:

m.optimize()
print(mQuadExpr.getValue()[0, 0])

item()¶

Get the unique expression contained in the current MQuadExpr.

example:

mat = m.addMVar((2, 2))
mQuadExpr = mat * mat[0, 0].item()
first = mQuadExpr[0, 0]
print(type(first))
print(type(first.item()))

Note

An exception is thrown if the current MQuadExpr contains more than one expression.

sum(axis=None)¶

Sum all included expressions and return the summed result.

Parameters: axis=None – Sum along the axis

example:

mat = m.addMVar((2, 2))
mQuadExpr = mat * mat[0, 0].item()
print(mQuadExpr.sum().size == 1)