# jacobian.py¶

Define the base Jacobian class.

class`openmdao.jacobians.jacobian.`

`Jacobian`

(system)[source]Bases:

`object`

Base Jacobian class.

This class provides a dictionary interface for sub-Jacobians and performs matrix-vector products when apply_linear is called.

- Attributes

_system<System>Pointer to the system that is currently operating on this Jacobian.

_subjacs_infodictDictionary of the sub-Jacobian metadata keyed by absolute names.

_under_complex_stepboolWhen True, this Jacobian is under complex step, using a complex jacobian.

_abs_keysdefaultdictA cache dict for key to absolute key.

_randomizeboolIf True, sparsity is being computed for simultaneous derivative coloring.

_col_var_infodictMaps column name to start, end, and slice/indices into the result array.

_colnameslistList of column var names.

_col2name_indndarrayArray that maps jac col index to index of column name.

`__contains__`

(key)[source]Return whether there is a subjac for the given promoted or relative name pair.

- Parameters

key(str, str)Promoted or relative name pair of sub-Jacobian.

- Returns

- boolean
return whether sub-Jacobian has been defined.

`__getitem__`

(key)[source]Get sub-Jacobian.

- Parameters

key(str, str)Promoted or relative name pair of sub-Jacobian.

- Returns

- ndarray or spmatrix or list[3]
sub-Jacobian as an array, sparse mtx, or AIJ/IJ list or tuple.

`__init__`

(system)[source]Initialize all attributes.

- Parameters

systemSystemParent system to this jacobian.

`__iter__`

()[source]Yield next name pair of sub-Jacobian.

`__setitem__`

(key,subjac)[source]Set sub-Jacobian.

- Parameters

key(str, str)Promoted or relative name pair of sub-Jacobian.

subjacint or float or ndarray or sparse matrixsub-Jacobian as a scalar, vector, array, or AIJ list or tuple.

`items`

()[source]Yield name pair and value of sub-Jacobian.

`keys`

()[source]Yield next name pair of sub-Jacobian.

property`msginfo`

Return info to prepend to messages.

- Returns

- str
Info to prepend to messages.

`set_col`

(system,icol,column)[source]Set a column of the jacobian.

The column is assumed to be the same size as a column of the jacobian.

This also assumes that the column does not attempt to set any nonzero values that are outside of specified sparsity patterns for any of the subjacs.

- Parameters

systemSystemThe system that owns this jacobian.

icolintColumn index.

columnndarrayColumn value.

`set_complex_step_mode`

(active)[source]Turn on or off complex stepping mode.

When turned on, the value in each subjac is cast as complex, and when turned off, they are returned to real values.

- Parameters

activeboolComplex mode flag; set to True prior to commencing complex step.

`openmdao.jacobians.jacobian.`

`rand`

(d0,d1,...,dn)Random values in a given shape.

Note

This is a convenience function for users porting code from Matlab, and wraps random_sample. That function takes a tuple to specify the size of the output, which is consistent with other NumPy functions like numpy.zeros and numpy.ones.

Create an array of the given shape and populate it with random samples from a uniform distribution over

`[0, 1)`

.

- Parameters

d0, d1, …, dnint, optionalThe dimensions of the returned array, must be non-negative. If no argument is given a single Python float is returned.

- Returns

outndarray, shape`(d0, d1, ..., dn)`

Random values.

See also

`random`

Examples

>>> np.random.rand(3,2) array([[ 0.14022471, 0.96360618], #random [ 0.37601032, 0.25528411], #random [ 0.49313049, 0.94909878]]) #random