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Errors and limits#

to_spec refuses a broken file before you attach data, and advice warns about a file that loads but looks wrong.

What to_spec checks#

to_spec attaches no data. Before it returns a Spec, it parses the file, resolves every name, checks every dimension rule and every degree, and reads every where string and every macro template, including the templates that nothing calls. A piecewise: entry is checked against every rule its expansion would be held to. Everything the language refuses, to_spec refuses there.

Every message names what went wrong and what to do about it:

Constraint 'balance': 'p_charge' not found.
  Variables: ['dispatch', 'soc']
  Parameters: ['capacity', 'efficiency', 'load']
Check the spelling, or declare 'p_charge'.

What advice warns about#

ms.advice(spec) returns a tuple of mathspec.program.Advice, one per warning, and python -m mathspec check spec.yaml prints them. Advice is only a warning, so the file still loads.

kind The file has… The advice says…
never-an-axis a dimension nothing is indexed by, nothing aggregates into and no relation targets remove it, or keep it knowingly if its entries are still to come
given a parameter, column, named expression or row family it reads and does not build (given) the model this one is layered onto provides it
unbounded a variable that no constraint, set or curve uses, whose objective term pushes it towards a bound it does not have give it a finite bound, or the constraint that was meant to define it 
Variable 'slack' makes this spec unbounded: no constraint names it, and
bounds.lower is open, and the +slack term in the minimize objective improves
toward it.
Give it a finite bounds.lower, or the constraint that was meant to define it.

advice is silent where the answer depends on the data: an objective coefficient that is a parameter, or a where: that leaves one slice of a variable with no constraint row.

Which error you get#

Class Subclass of
MathSpecError ValueError The root
LanguageError MathSpecError Something in the spec: a construct outside the language, a dimension set that does not compose, or a name that nothing declares
SchemaError LanguageError Something in the file: an unknown key, a malformed entry, or a bad symbol table
DimensionError LanguageError Dimensions that disagree, such as a constraint whose expression does not equal its dims

You can reproduce each of these errors from the YAML alone.

What the language will not express#

The limits list what the language refuses, and what to write instead.