|
49 | 49 | from .statesp import StateSpace |
50 | 50 | from .statefbk import gram |
51 | 51 |
|
52 | | -__all__ = ['hsvd', 'balred', 'modred', 'era', 'markov', 'minreal'] |
| 52 | +__all__ = ['hankel_singular_values', 'balanced_reduction', 'model_reduction', |
| 53 | + 'minimal_realization', 'eigensys_realization', 'markov', 'hsvd', |
| 54 | + 'balred', 'modred', 'minreal', 'era'] |
53 | 55 |
|
54 | 56 |
|
55 | 57 | # Hankel Singular Value Decomposition |
56 | 58 | # |
57 | 59 | # The following returns the Hankel singular values, which are singular values |
58 | 60 | # of the matrix formed by multiplying the controllability and observability |
59 | 61 | # Gramians |
60 | | -def hsvd(sys): |
| 62 | +def hankel_singular_values(sys): |
61 | 63 | """Calculate the Hankel singular values. |
62 | 64 |
|
63 | 65 | Parameters |
@@ -106,7 +108,7 @@ def hsvd(sys): |
106 | 108 | return hsv[::-1] |
107 | 109 |
|
108 | 110 |
|
109 | | -def modred(sys, ELIM, method='matchdc'): |
| 111 | +def model_reduction(sys, ELIM, method='matchdc'): |
110 | 112 | """ |
111 | 113 | Model reduction of `sys` by eliminating the states in `ELIM` using a given |
112 | 114 | method. |
@@ -216,7 +218,7 @@ def modred(sys, ELIM, method='matchdc'): |
216 | 218 | return rsys |
217 | 219 |
|
218 | 220 |
|
219 | | -def balred(sys, orders, method='truncate', alpha=None): |
| 221 | +def balanced_reduction(sys, orders, method='truncate', alpha=None): |
220 | 222 | """Balanced reduced order model of sys of a given order. |
221 | 223 | States are eliminated based on Hankel singular value. |
222 | 224 | If sys has unstable modes, they are removed, the |
@@ -340,7 +342,7 @@ def balred(sys, orders, method='truncate', alpha=None): |
340 | 342 | return rsys |
341 | 343 |
|
342 | 344 |
|
343 | | -def minreal(sys, tol=None, verbose=True): |
| 345 | +def minimal_realization(sys, tol=None, verbose=True): |
344 | 346 | ''' |
345 | 347 | Eliminates uncontrollable or unobservable states in state-space |
346 | 348 | models or cancelling pole-zero pairs in transfer functions. The |
@@ -368,7 +370,7 @@ def minreal(sys, tol=None, verbose=True): |
368 | 370 | return sysr |
369 | 371 |
|
370 | 372 |
|
371 | | -def era(YY, m, n, nin, nout, r): |
| 373 | +def eigensys_realization(YY, m, n, nin, nout, r): |
372 | 374 | """Calculate an ERA model of order `r` based on the impulse-response data |
373 | 375 | `YY`. |
374 | 376 |
|
@@ -556,3 +558,10 @@ def markov(Y, U, m=None, transpose=False): |
556 | 558 |
|
557 | 559 | # Return the first m Markov parameters |
558 | 560 | return H if transpose else np.transpose(H) |
| 561 | + |
| 562 | +# Function aliases |
| 563 | +hsvd = hankel_singular_values |
| 564 | +balred = balanced_reduction |
| 565 | +modred = model_reduction |
| 566 | +minreal = minimal_realization |
| 567 | +era = eigensys_realization |
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