Changeset 5753:e207e63d5ceb for sage/calculus/desolvers.py
- Timestamp:
- 08/12/07 18:38:20 (6 years ago)
- Branch:
- default
- Parents:
- 5644:6b03fe2cf6a5 (diff), 5752:595c003bb14e (diff)
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sage/calculus/desolvers.py (modified) (6 diffs)
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sage/calculus/desolvers.py
r5752 r5753 54 54 55 55 EXAMPLES: 56 sage: desolve ("x**2*diff(y,x) + 3*y*x = sin(x)/x",["x","y"])56 sage: desolvers.desolve("x**2*diff(y,x) + 3*y*x = sin(x)/x",["x","y"]) 57 57 y=(%c-cos(x))/x^3 58 58 … … 81 81 82 82 EXAMPLES: 83 sage: desolve _laplace("diff(f(x),x,2)=2*diff(f(x),x)-f(x)",["x","f"])83 sage: desolvers.desolve_laplace("diff(f(x),x,2)=2*diff(f(x),x)-f(x)",["x","f"]) 84 84 f(x)=x*%e^x*(?%at('diff(f(x),x,1),x=0))-f(0)*x*%e^x+f(0)*%e^x 85 sage: desolve _laplace("diff(f(x),x,2)=2*diff(f(x),x)-f(x)",["x","f"],[0,1,2])85 sage: desolvers.desolve_laplace("diff(f(x),x,2)=2*diff(f(x),x)-f(x)",["x","f"],[0,1,2]) 86 86 f(x)=x*%e^x+%e^x 87 87 … … 127 127 sage: des=["'diff(x(t),t)=-4*y(t)","'diff(y(t),t)=-x(t)"] 128 128 sage: vars = ["t","x","y"] 129 sage: desolve _system(des,vars)129 sage: desolvers.desolve_system(des,vars) 130 130 [x(t)=(2*y(0)+x(0))*%e^-(2*t)/2-(2*y(0)-x(0))*%e^(2*t)/2,y(t)=(2*y(0)-x(0))*%e^(2*t)/4+(2*y(0)+x(0))*%e^-(2*t)/4] 131 131 sage: des=["'diff(x(t),t)=-4*y(t)","'diff(y(t),t)=-x(t)"] 132 132 sage: vars = ["t","x","y"] 133 sage: desolve _system(des,vars,[0,270,90])133 sage: desolvers.desolve_system(des,vars,[0,270,90]) 134 134 [x(t)=45*%e^(2*t)+225*%e^-(2*t),y(t)=225*%e^-(2*t)/2-45*%e^(2*t)/2] 135 135 sage: des=["'diff(x(t),t)=-4*y(t)","'diff(y(t),t)=-z(t)","'diff(z(t),t)=-2*x(t)"] 136 136 sage: vars = ["t","x","y","z"] 137 137 sage: ics=[0,270,90,100] 138 sage: desolve _system(des,vars,ics)138 sage: desolvers.desolve_system(des,vars,ics) 139 139 [x(t)=%e^t*(260*cos(sqrt(3)*t)/3-80*sin(sqrt(3)*t)/sqrt(3))+550*%e^-(2*t)/3,y(t)=%e^t*(85*sin(sqrt(3)*t)/sqrt(3)-5*cos(sqrt(3)*t)/3)+275*%e^-(2*t)/3,z(t)=%e^t*(-90*sin(sqrt(3)*t)/sqrt(3)-250*cos(sqrt(3)*t)/3)+550*%e^-(2*t)/3] 140 140 … … 172 172 173 173 EXAMPLES: 174 sage.:. x,y = PolynomialRing(QQ,2,"xy").gens()175 sage.:. eulers_method(5*x+y-5,0,1,1/2,1)176 x y h*f(x,y)177 0 1 -2178 1/2 -1 -7/4179 1 -11/4 -11/8180 174 sage: x,y = PolynomialRing(QQ,2,"xy").gens() 181 sage: eulers_method(5*x+y-5,0,1,1/2,1,method="none")175 sage: desolvers.eulers_method(5*x+y-5,0,1,1/2,1,method="none") 182 176 [[0, 1], [1/2, -1], [1, -11/4], [3/2, -33/8]] 183 177 sage: RR = RealField(sci_not=0, prec=4, rnd='RNDU') 184 178 sage: x,y = PolynomialRing(RR,2,"xy").gens() 185 sage: eulers_method(5*x+y-5,0,1,1/2,1,method="None")179 sage: desolvers.eulers_method(5*x+y-5,0,1,1/2,1,method="None") 186 180 [[0, 1], [1/2, -1.0], [1, -2.7], [3/2, -4.0]] 187 sage .:.RR = RealField(sci_not=0, prec=4, rnd='RNDU')188 sage .:.x,y=PolynomialRing(RR,2,"xy").gens()189 sage .:.eulers_method(5*x+y-5,0,1,1/2,1)181 sage: RR = RealField(sci_not=0, prec=4, rnd='RNDU') 182 sage: x,y=PolynomialRing(RR,2,"xy").gens() 183 sage: desolvers.eulers_method(5*x+y-5,0,1,1/2,1) 190 184 x y h*f(x,y) 191 185 0 1 -2.00 … … 228 222 sage: eulers_method_2x2(f,g, 0, 0, 0, 1/3, 1,method="none") 229 223 [[0, 0, 0], [1/3, 0, 0], [2/3, 1/9, 0], [1, 10/27, 1/27], [4/3, 68/81, 4/27]] 230 sage .:.eulers_method_2x2(f,g, 0, 0, 0, 1/3, 1)224 sage: desolvers.eulers_method_2x2(f,g, 0, 0, 0, 1/3, 1) 231 225 t x h*f(t,x,y) y h*g(t,x,y) 232 226 0 0 0 0 0 … … 234 228 2/3 1/9 7/27 0 1/27 235 229 1 10/27 38/81 1/27 1/9 236 sage .: RR = RealField(sci_not=0, prec=4, rnd='RNDU')237 sage .: t,x,y=PolynomialRing(RR,3,"txy").gens()238 sage .: f = x+y+t; g = x-y239 sage .:.eulers_method_2x2(f,g, 0, 0, 0, 1/3, 1)230 sage: RR = RealField(sci_not=0, prec=4, rnd='RNDU') 231 sage: t,x,y=PolynomialRing(RR,3,"txy").gens() 232 sage: f = x+y+t; g = x-y 233 sage: eulers_method_2x2(f,g, 0, 0, 0, 1/3, 1) 240 234 t x h*f(t,x,y) y h*g(t,x,y) 241 235 0 0 0.000 0 0.000
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