deqatn
Module¶
Defines the DEQATN class and sub-functions.
The capitalization of the sub-functions is important.
-
class
pyNastran.bdf.cards.deqatn.
DEQATN
(equation_id, eqs, comment='')[source]¶ Bases:
pyNastran.bdf.cards.base_card.BaseCard
Design Equation Definition Defines one or more equations for use in design sensitivity analysis.
1
2
3
4
5
6
7
8
DEQATN
EQID
EQUATION
EQUATION (cont.)
Creates a DEQATN card
- Parameters
- equation_idint
the id of the equation
- eqsList[str]
the equations, which may overbound the field split them by a semicolon (;)
- commentstr; default=’’
a comment for the card
- DEQATN 41 F1(A,B,C,D,R) = A+B *C–(D**3 + 10.0) + sin(PI(1) * R)
A**2 / (B - C); F = A + B - F1 * D
- def F1(A, B, C, D, R):
F1 = A+B *C-(D**3 + 10.0) + sin(PI(1) * R) + A**2 / (B – C) F = A + B - F1 * D return F
- eqs = [
‘F1(A,B,C,D,R) = A+B *C–(D**3 + 10.0) + sin(PI(1) * R) + A**2 / (B – C)’, ‘F = A + B – F1 * D’,
- ]
- >>> deqatn = DEQATN(41, eq, comment=’’)
-
_properties
= ['dtable']¶
-
_setup_equation
() → None[source]¶ creates an executable equation object from self.eqs
x = 10. >>> deqatn.func(x) 42.0
>>> deqatn.func_str def stress(x): x = float(x) return x + 32.
-
classmethod
add_card
(card: List[str], comment: str = '')[source]¶ Adds a DEQATN card from
BDF.add_card(...)
- Parameters
- cardList[str]
this card is special and is not a
BDFCard
like other cards- commentstr; default=’’
a comment for the card
-
cross_reference
(model: BDF) → None[source]¶ Cross links the card so referenced cards can be extracted directly
- Parameters
- modelBDF()
the BDF object
-
repr_fields
() → List[str][source]¶ Gets the fields in their simplified form
- Returns
- fieldsList[varies]
the fields that define the card
-
type
= 'DEQATN'¶
-
pyNastran.bdf.cards.deqatn.
_join_wrapped_equation_lines
(unused_eqs_temp_in, eqs_temp: List[str]) → List[str][source]¶ helper for
lines_to_eqs
-
pyNastran.bdf.cards.deqatn.
_split_equation
(lines_out: List[str], line: str, n: int, isplit: int = 0) → List[str][source]¶ Takes an overbounded DEQATN line and shortens it using recursion
- Parameters
- lines_outList[str]
len(lines) = 0 : first iteration len(lines) = 1 : second iteration
- linestr
the line to split
- nint
the maximum number of characters allowed the first line of the DEQATN has a different number of fields allowed vs. subsequent lines
- isplitint; default=0
the number of levels deep in the recursive function we are
- Returns
- lines_outList[str]
the long line broken into shorter lines
-
pyNastran.bdf.cards.deqatn.
_split_equations_by_semicolon
(eqs_in: List[str]) → List[str][source]¶ helper for
lines_to_eqs
-
pyNastran.bdf.cards.deqatn.
_write_comment
(comment: str) → str[source]¶ writes the deqatn to the comment block
-
pyNastran.bdf.cards.deqatn.
_write_function_line
(func_name: str, variables: List[str], default_values: Dict[str, float]) → str[source]¶ writes the
def f(x, y, z=1.):
part of the function
-
pyNastran.bdf.cards.deqatn.
_write_variables
(variables: List[str]) → str[source]¶ type checks the inputs
-
pyNastran.bdf.cards.deqatn.
atan2h
(x, y)[source]¶ Hyperbolic arctangent >>> arctanh(z) = 1/2 Log((1+z)/(1-z))
- real:
- complex:
x1 = a + bi x2 = b + di a = b = 0 and (sign of c) = (sign of d):
the result is 0.
- a = b = 0 and (sign of c) ≠ (sign of d):
the result is π.
- c = d = 0 and (sign of a) = (sign of b):
the result is π/2.
- c = d = 0 and (sign of a) ≠ (sign of b):
the result is −π/2
-
pyNastran.bdf.cards.deqatn.
dba
(p: float, pref: float, f: float) → float[source]¶ sound pressure in decibels (perceived)
- Parameters
- pfloat
structural responses or acoustic pressure
- ffloat
forcing frequency
- preffloat
reference pressure
- Returns
- dbifloat
acoustic pressure in Decibels
-
pyNastran.bdf.cards.deqatn.
fortran_to_python
(deqatn_id: int, lines: List[str], default_values: Dict[str, Union[float, numpy.ndarray]], comment: str = '') → Tuple[str, int, str][source]¶ Creates the python function
- Parameters
- linesList[str]
the equations to write broken up by statement
- default_valuesdict[name] = value
the default values from the DTABLE card
- Returns
- func_namestr
the name of the function
- nargsint
the number of variables to the function
- func_msgstr
the python function
- def f(x, y=10.):
‘’’ $ deqatn DEQATN 1000 f(x,y) = x+y ‘’’ try:
- if isinstance(x, (int, float, str)):
x = float(x)
- if isinstance(y, (int, float, str)):
y = float(y)
- except Exception:
print(locals()) raise
f = x + y return f
-
pyNastran.bdf.cards.deqatn.
fortran_to_python_short
(line: str, unused_default_values: Any) → Any[source]¶ the function used by the DRESP2
-
pyNastran.bdf.cards.deqatn.
invdba
(dbai: float, pref: float, f: float) → float[source]¶ Inverse Dba
- Parameters
- dbaifloat
acoustic pressure in Decibels (perceived)
- ffloat
forcing frequency
- preffloat
reference pressure
- Returns
- pfloat
structural responses or acoustic pressure
-
pyNastran.bdf.cards.deqatn.
lines_to_eqs
(eqs_in: List[str]) → List[str][source]¶ splits the equations
-
pyNastran.bdf.cards.deqatn.
rss
(*args)[source]¶ 2-norm; generalized magnitude of vector for N components
-
pyNastran.bdf.cards.deqatn.
split_equations
(lines: List[str]) → List[str][source]¶ takes an overbounded DEQATN card and shortens it
-
pyNastran.bdf.cards.deqatn.
split_to_equations
(lines: List[str]) → List[str][source]¶ Splits a line like:
b = a + z; c = 42
into:
b = a + z c = 42
-
pyNastran.bdf.cards.deqatn.
write_function_header
(func_header: str, eq: str, default_values: Dict[str, float], comment: str = '') → Tuple[str, str, List[str]][source]¶ initializes the python function
- def f(x, y=10.):
‘’’ $ deqatn DEQATN 1000 f(x,y) = x+y ‘’’ try:
- if isinstance(x, (int, float, str)):
x = float(x)
- if isinstance(y, (int, float, str)):
y = float(y)
- except Exception:
print(locals()) raise
- Parameters
- fstr
the function header f(a, b, c)
- eqstr
the value on the other side of the equals sign (f=eq) 1. max(a, b, c)
- default_valuesdict[name] = value
the default values from the DTABLE card
- Returns
- func_namestr
the name of the function
f
- msgstr
see above
- variablesList[str]
the variables used by the equation header a, b, c