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Lecture 28k, extending to 8 dimensions

Just extending seventh order PDE in four dimensions, to eight dimensions

Desired solution is U(x,y,z,t,u,v,w,p), given PDE: ∇4U + 2 ∇2U + 8 U = f(x,y,z,t,u,v,w,p) ∂4U(x,y,z,t,u,v,w,p)/∂x4 + ∂4U(x,y,z,t,u,v,w,p)/∂y4 + ∂4U(x,y,z,t,u,v,w,p)/∂z4 + ∂4U(x,y,z,t,u,v,w,p)/∂t4 + ∂4U(x,y,z,t,u,v,w,p)/∂u4 + ∂4U(x,y,z,t,u,v,w,p)/∂v4 + ∂4U(x,y,z,t,u,v,w,p)/∂w4 + ∂4U(x,y,z,t,u,v,w,p)/∂p4 + 2 ∂2U(x,y,z,t,u,v,w,p)/∂x2 + 2 ∂2U(x,y,z,t,u,v,w,p)/∂y2 + 2 ∂2U(x,y,z,t,u,v,w,p)/∂z2 + 2 ∂2U(x,y,z,t,u,v,w,p)/∂t2 + 2 ∂2U(x,y,z,t,u,v,w,p)/∂u2 + 2 ∂2U(x,y,z,t,u,v,w,p)/∂v2 + 2 ∂2U(x,y,z,t,u,v,w,p)/∂w2 + 2 ∂2U(x,y,z,t,u,v,w,p)/∂p2 + 8 U(x,y,z,t,u,v,w,p) = f(x,y,z,t,u,v,w,p)

Test a fourth order PDE in eight dimensions.

4U + 2 ∇2U + 8 U = f(x,y,z,t,u,v,w,p) pde48hn_eq.java solver source code pde48hn_eq_java.out verification output ∇4U + 2 ∇2U + 8 U = f(x,y,z,t,u,v,w,p) pde48hn_eq.c solver source code pde48hn_eq_c.out verification output pde48hn_eq.adb solver source code pde48hn_eq_ada.out verification output pde48h_eq.adb solver source code pde48h_eq_ada.out verification output

Some programs above also need:

nuderiv.java basic non uniform grid derivative rderiv.java basic uniform grid derivative simeq.java basic simultaneous equation deriv.h basic derivatives deriv.c basic derivatives real_arrays.ads 2D arrays and operations real_arrays.adb 2D arrays and operations integer_arrays.ads 2D arrays and operations integer_arrays.adb 2D arrays and operations rderiv.adb derivative computation inverse.adb inverse computation Plotted output from pde48hn_eq.java execution plot8d.java source code User can select any two variables for 3D view. User can select values for other variables, option to run all cases. Then, going to a spherical coordinate system in 8 dimensions gen_8d_sphere.c source equations gen_8d_sphere_c.out verification output

The above was all Cartesian Coordinates, now Spherical Coordinates

faces.c source code for output faces.out output for n dimensional cube and spheretest_faces.c source code for test test_faces.out output of test faces.java source code for output faces_java.out output for n dimensional cube and sphere test_faces.java source code for test test_faces_java.out equations and test faces.py source code for output faces_py.out output for n dimensional cube and sphere faces.java running, data for various n-cubes, n-spheres, n dimensions edge length L for cubes, radius R for spheres 0-cube point vertices = 1 n=1-cube line edges = 1 length=L vertices = 2 n=2-cube square 2D faces = 1 area= L^2 edges = 4 length=4*L vertices = 4 n=3-cube cube cubes = 1 volume= L^3 2D faces = 6 area= 6*L^2 edges = 12 length=12*L vertices = 8 n=4-cube 4-cubes = 1 volume= L^4 cubes = 8 volume= 8*L^3 2D faces = 24 area= 24*L^2 edges = 32 length=32*L vertices = 16 n=5-cube 5-cubes = 1 volume= L^5 4-cubes = 10 volume=10*L^4 cubes = 40 volume=40*L^3 2D faces = 80 area= 80*L^2 edges = 80 length=80*L vertices = 32 n=6-cube 6-cubes = 1 volume= L^6 5-cubes = 12 volume= 12*L^5 4-cubes = 60 volume= 60*L^4 cubes = 160 volume=160*L^3 2D faces = 240 area= 240*L^2 edges = 192 length=192*L vertices = 64 n=7-cube 7-cubes = 1 volume= L^7 6-cubes = 14 volume= 14*L^6 5-cubes = 84 volume= 84*L^5 4-cubes = 280 volume=280*L^4 cubes = 560 volume=560*L^3 2D faces = 672 area= 672*L^2 edges = 448 length=448*L vertices = 128 n=8-cube 8-cubes = 1 volume= L^8 7-cubes = 16 volume= 16*L^7 6-cubes = 112 volume= 112*L^6 5-cubes = 448 volume= 448*L^5 4-cubes = 1120 volume=1120*L^4 cubes = 1792 volume=17928L^3 2D faces = 1792 area= 1792*L^2 edges = 1024 length=1024*L vertices = 256 n=9-cube 9-cubes = 1 volume= L^9 8-cubes = 18 volume= 18*L^8 7-cubes = 144 volume= 144*L^7 6-cubes = 672 volume= 672*L^6 5-cubes = 2016 volume=2016*L^5 4-cubes = 4032 volume=4032*L^4 cubes = 5376 volume=5376*L^3 2D faces = 4608 area= 4608*L^2 edges = 2304 length=2304*L vertices = 512 n=10-cube 10-cubes = 1 volume= L^10 9-cubes = 20 volume= 20*L^9 8-cubes = 180 volume= 180*L^8 7-cubes = 960 volume= 960*L^7 6-cubes = 3360 volume= 3360*L^6 5-cubes = 8064 volume= 8064*L^5 4-cubes = 13440 volume=13440*L^4 cubes = 15360 volume=15360*L^3 2D faces = 11520 area= 11520*L^2 edges = 5120 length= 5120*L vertices = 1024 cubes of n dimensions with edge length E, n>=3, volume = E^n, area=(2D faces)*E*E n-cube has 2^n vertex, with n edges at each vertex n>=m, there are pwr2(n-m)*comb(n,m) n-m sub cubes Spheres up to 10 dimensions D-1 surface D volume 2D circle 2 Pi R 1 Pi R^2 3D sphere 4 Pi R^2 4/3 Pi R^3 4D 4-sphere 2 Pi^2 R^3 1/2 Pi^2 R^4 5D 5-sphere 8/3 Pi^2 R^4 8/15 Pi^2 R^5 6D 6-sphere 1 Pi^3 R^5 1/6 Pi^3 R^6 7D 7-sphere 16/15 Pi^3 R^6 16/105 Pi^3 R^7 8D 8-sphere 1/3 Pi^4 R^7 1/24 Pi^4 R^8 9D 9-sphere 32/105 Pi^4 R^8 32/945 Pi^4 R^9 10D 10-sphere 1/12 Pi^5 R^9 1/120 Pi^5 R^10 volume V_n(R)= Pi^(n/2) R^n / gamma(n/2+1) gamma(integer) = factorial(integer-1) gamma(5) = 24 gamma(1/2) = sqrt(Pi), gamma(n/2+1) = (2n)! sqrt(Pi)/(4^n n!) or V_2k(R) = Pi^k R^2k/k! , V_2k+1 = 2 k! (4Pi)^k R^(2k+1)/(2k+1)! surface area A_n(R) = d/dR V_n(R) one definition of sequence of n-spheres a1, a2, a3, a4, a5, a6, a7 are angles, typ: theta, phi, ... x1, x2, x3, x4, x5, x6, x7, x8 are orthogonal coordinates x1^2 + x2^2 + x3^2 + x4^2 + x5^2 + x6^2 + x7^2 +x8^2 = R^2 Radius R = sqrt(R^2) 2D circle x1 = R cos(a1) typ: x theta x2 = R sin(a1) typ: y theta a1 = arctan(x2/x1) or a1 = acos(x1/R) 3D sphere x1 = R cos(a1) typ: z phi x2 = R sin(a1) cos(a2) typ: x phi theta x3 = R sin(a1) sin(a2) typ: y phi theta a1 = arctan(sqrt(x2^2+x3^2)/x1) or a1 = acos(x1/R) a2 = arctan(x3/x2) or a2 = acos(x2/sqrt(x2^2+x3^2)) 4D 4-sphere continuing systematic notation, notice pattern x1 = R cos(a1) x2 = R sin(a1) cos(a2) x3 = R sin(a1) sin(a2) cos(a3) x4 = R sin(a1) sin(a2) sin(a3) a1 = acos(x1/sqrt(x1^2+x2^2+x3^2+x4^2)) a2 = acos(x2/sqrt(x2^2+x3^2+x4^2)) a3 = acos(x3/sqrt(x3^2+x4^2)) if x4>=0 a3 = 2 Pi - acos(x3/sqrt(x3^2+x4^2)) if x4<0 5D 5-sphere x1 = R cos(a1) x2 = R sin(a1) cos(a2) x3 = R sin(a1) sin(a2) cos(a3) x4 = R sin(a1) sin(a2) sin(a3) cos(a4) x5 = R sin(a1) sin(a2) sin(a3) sin(a4) a1 = acos(x1/sqrt(x1^2+x2^2+x3^2+x4^2+x5^2)) a2 = acos(x2/sqrt(x2^2+x3^2+x4^2+x5^2)) a3 = acos(x3/sqrt(x3^2+x4^2+x5^2)) a4 = acos(x4/sqrt(x4^2+x5^2)) if x5>=0 a4 = 2 Pi - acos(x4/sqrt(x4^2+x5^2)) if x5<0 6D 6-sphere x1 = R cos(a1) x2 = R sin(a1) cos(a2) x3 = R sin(a1) sin(a2) cos(a3) x4 = R sin(a1) sin(a2) sin(a3) cos(a4) x5 = R sin(a1) sin(a2) sin(a3) sin(a4) cos(a5) x6 = R sin(a1) sin(a2) sin(a3) sin(a4) sin(a5) a1 = acos(x1/sqrt(x1^2+x2^2+x3^2+x4^2+x5^2+x6^2)) a2 = acos(x2/sqrt(x2^2+x3^2+x4^2+x5^2+x6^2)) a3 = acos(x3/sqrt(x3^2+x4^2+x5^2+x6^2)) a4 = acos(x4/sqrt(x4^2+x5^2+x6^2)) a5 = acos(x5/sqrt(x5^2+x6^2)) if x6>=0 a5 = 2 Pi - acos(x5/sqrt(x5^2+x6^2)) if x6<0 7D 7-sphere x1 = R cos(a1) x2 = R sin(a1) cos(a2) x3 = R sin(a1) sin(a2) cos(a3) x4 = R sin(a1) sin(a2) sin(a3) cos(a4) x5 = R sin(a1) sin(a2) sin(a3) sin(a4) cos(a5) x6 = R sin(a1) sin(a2) sin(a3) sin(a4) sin(a5) cos(a6) x7 = R sin(a1) sin(a2) sin(a3) sin(a4) sin(a5) sin(a6) a1 = acos(x1/sqrt(x1^2+x2^2+x3^2+x4^2+x5^2+x6^2+x7^2)) a2 = acos(x2/sqrt(x2^2+x3^2+x4^2+x5^2+x6^2+x7^2)) a3 = acos(x3/sqrt(x3^2+x4^2+x5^2+x6^2+x7^2)) a4 = acos(x4/sqrt(x4^2+x5^2+x6^2+x7^2)) a5 = acos(x5/sqrt(x5^2+x6^2+x7^2)) a6 = acos(x6/sqrt(x6^2+x6^2)) if x7>=0 a6 = 2 Pi - acos(x6/sqrt(x6^2+x7^2)) if x7<0 8D 8-sphere x1 = R cos(a1) x2 = R sin(a1) cos(a2) x3 = R sin(a1) sin(a2) cos(a3) x4 = R sin(a1) sin(a2) sin(a3) cos(a4) x5 = R sin(a1) sin(a2) sin(a3) sin(a4) cos(a5) x6 = R sin(a1) sin(a2) sin(a3) sin(a4) sin(a5) cos(a6) x7 = R sin(a1) sin(a2) sin(a3) sin(a4) sin(a5) sin(a6) cos(a7) x8 = R sin(a1) sin(a2) sin(a3) sin(a4) sin(a5) sin(a6) sin(a7) a1 = acos(x1/sqrt(x1^2+x2^2+x3^2+x4^2+x5^2+x6^2+x7^2+x8^2)) a2 = acos(x2/sqrt(x2^2+x3^2+x4^2+x5^2+x6^2+x7^2+x8^2)) a3 = acos(x3/sqrt(x3^2+x4^2+x5^2+x6^2+x7^2+x8^2)) a4 = acos(x4/sqrt(x4^2+x5^2+x6^2+x7^2+x8^2)) a5 = acos(x5/sqrt(x5^2+x6^2+x7^2+x8^2)) a6 = acos(x6/sqrt(x5^2+x6^2+x7^2+x8^2)) a7 = acos(x7/sqrt(x7^2+x8^2)) if x8>=0 a7 = 2 Pi - acos(x7/sqrt(x7^2+x8^2)) if x8<0 faces.java finished It is left as an exercise to student to develop equations for gradient and laplacian 4D to 8D spheres.

You won't find many open source or commercial 8D PDE packages

many lesser problems have many open source and commercial packages

en.wikipedia.org/wiki/list_of_finite_element_software_packages
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