Attention

HELP WANTED
Please start by reading the guide to contributing to the Brightway documentation.

Warning

NEEDS WORK
It is either a rough draft or has been copied over from the legacy documentation.

# Normal Static LCA#

The actual LCA class (bw2calc.LCA) is more of a coordinator then an accountant, as the matrix builder is doing much of the data manipulation. The lca{.interpreted-text role=”ref”} class only has to do the following:

• Translate the functional unit into a demand array

• Find the right parameter arrays, and ask matrix builder for matrices

• Solve the linear system $$Ax=B$$ using SuperLU or UMFpack.

• Multiply the result by the LCIA CFs, if a LCIA method is present

Due to licensing conflicts, recent versions of SciPy do not include UMFpack. UMFpack is faster than SuperLU, especially for repeated calculations. Python wrappers for UMFpack must be installed separately using scikits.umfpack.

The LCA class also has some convenience functions for redoing some calculations with slight changes, e.g. for uncertainty and sensitivity analysis. See the redo()*\ and rebuild_* methods in the LCA class.