CoCalc -- 2016-02-10-013229.sagews

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y=3/5

y.n()

0.600000000000000

type(y)

<type 'sage.rings.rational.Rational'>

load("test_integers.py")

3/5 = 0

0

A = [[0 for j in range(15180)] for i in range(26620)]


#I am interpolating the uniformly space points, chevyshev and legendre polynomial over the interval [-1,2] with the lagrange form then finding the l^2 and l^inf norms to find the error.  I am not sure what is going wrong....



OP0=-1
OP1=0
OP2=1
OP3=2

ONUME0=(x-OP1)*(x-OP2)*(x-OP3)
ONUME1=(x-OP0)*(x-OP2)*(x-OP3)
ONUME2=(x-OP0)*(x-OP1)*(x-OP3)
ONUME3=(x-OP0)*(x-OP1)*(x-OP3)

ODENO0=(OP0-OP1)*(OP0-OP2)*(OP0-OP3)
ODENO1=(OP1-OP0)*(OP1-OP2)*(OP1-OP3)
ODENO2=(OP2-OP0)*(OP2-OP1)*(OP2-OP3)
ODENO3=(OP3-OP0)*(OP3-OP1)*(OP3-OP2)

a=-1
b=2
n=3

i0=0
i1=1
i2=2
i3=3

A=((a+b)/2)
B=((b-a)/2)
E=(e^(-x))

OCLagr0=(ONUME0/ODENO0)
OCLagr1=B*(ONUME1/ODENO1)
OCLagr2=B*(ONUME2/ODENO2)
OCLagr3=B*(ONUME3/ODENO3)


Op0=(e^(-OCLagr0))
Op1=(e^(-OCLagr1))
Op2=(e^(-OCLagr2))
Op3=(e^(-OCLagr3))



Uniformly=((Op0*OCLagr0)+(OP1*OCLagr1)+(Op2*OCLagr2)+(Op3*OCLagr3))



#Lagrange Cheveyshev



C0= numerical_approx(cos((pi)*((2*i0+1)/(2*n+2))))
C1= numerical_approx(cos((pi)*((2*i1+1)/(2*n+2))))
C2= numerical_approx(cos((pi)*((2*i2+1)/(2*n+2))))
C3= numerical_approx(cos((pi)*((2*i3+1)/(2*n+2))))


CV0=((B*C0)+A)
CV1=((B*C1)+A)
CV2=((B*C2)+A)
CV3=((B*C3)+A)


xo=CV0
xi=CV1
xii=CV2
xiii=CV3


NUME0=(x-xi)*(x-xii)*(x-xiii)
NUME1=(x-xo)*(x-xii)*(x-xiii)
NUME2=(x-xo)*(x-xi)*(x-xiii)
NUME3=(x-xo)*(x-xi)*(x-xii)

DENO0=(xo-xi)*(xo-xii)*(xo-xiii)
DENO1=(xi-xo)*(xi-xii)*(xi-xiii)
DENO2=(xii-xo)*(xii-xi)*(xii-xiii)
DENO3=(xiii-xo)*(xiii-xi)*(xiii-xii)

CLagr0=(NUME0/DENO0)
CLagr1=(NUME1/DENO1)
CLagr2=(NUME2/DENO2)
CLagr3=(NUME3/DENO3)



P0=numerical_approx(e^(-(C0)))
P1=numerical_approx(e^(-(C1)))
P2=numerical_approx(e^(-(C2)))
P3=numerical_approx(e^(-(C3)))

F0=P0*CLagr0
F1=P1*CLagr1
F2=P2*CLagr2
F3=P3*CLagr3



Chevyshev=F0+F1+F2+F3


##Legendre

LP0=1
LP1=x
LP2=(1/2)*(3*((x)^2)-1)
LP3=(((1/2)*(((5)*x^2)-((3)*x))))
LP4=((1/8)*(((35)*x^4)-((30)*x^2)+3))

f=7*LP0
g=8*LP4
h=20*LP2
j=3*LP1
k=2*LP3


X1=numerical_approx(-sqrt(2/35*sqrt(30) + 3/7))
X2=numerical_approx(sqrt(2/35*sqrt(30) + 3/7))
X3=numerical_approx(-sqrt(-2/35*sqrt(30) + 3/7))
X4=numerical_approx(sqrt(-2/35*sqrt(30) + 3/7))


LOV0=((B*X1)+A)
LOV1=((B*X2)+A)
LOV2=((B*X3)+A)
LOV3=((B*X4)+A)

lxo=LOV0
lxi=LOV1
lxii=LOV2
lxiii=LOV3


LNUME0=(x-lxi)*(x-lxii)*(x-lxiii)
LNUME1=(x-lxo)*(x-lxii)*(x-lxiii)
LNUME2=(x-lxo)*(x-lxi)*(x-lxiii)
LNUME3=(x-lxo)*(x-lxi)*(x-lxii)

LDENO0=(lxo-lxi)*(lxo-lxii)*(lxo-lxiii)
LDENO1=(lxi-lxo)*(lxi-lxii)*(lxi-lxiii)
LDENO2=(lxii-lxo)*(lxii-lxi)*(lxii-lxiii)
LDENO3=(lxiii-lxo)*(lxiii-lxi)*(lxiii-lxii)

LLagr0=(LNUME0/LDENO0)
LLagr1=(LNUME1/LDENO1)
LLagr2=(LNUME2/LDENO2)
LLagr3=(LNUME3/LDENO3)


LP0=numerical_approx(e^(-(X1)))
LP1=numerical_approx(e^(-(X2)))
LP2=numerical_approx(e^(-(X3)))
LP3=numerical_approx(e^(-(X4)))

LF0=LP0*LLagr0
LF1=LP1*LLagr1
LF2=LP2*LLagr2
LF3=LP3*LLagr3

Legendere=LF0+LF1+LF2+LF3




f = (0.116167595984182*(x + 0.791704467391079)*(x + 0.00997156537728427)*(x - 1.00997156537728) - 0.495492470126893*(x + 0.791704467391079)*(x + 0.00997156537728427)*(x - 1.79170446739108) + 0.978004473650812*(x + 0.791704467391079)*(x - 1.00997156537728)*(x - 1.79170446739108) - 0.650217267384311*(x + 0.00997156537728427)*(x - 1.00997156537728)*(x - 1.79170446739108))^2

g=(e^-x)^2

h=(0.0900243711092997*(x + 0.885819298766930)*(x + 0.0740251485476346)*(x - 1.07402514854763) - 0.373399955130276*(x + 0.885819298766930)*(x + 0.0740251485476346)*(x - 1.88581929876693) + 0.802728841958563*(x + 0.885819298766930)*(x - 1.07402514854763)*(x - 1.88581929876693) - 0.571257167284918*(x + 0.0740251485476346)*(x - 1.07402514854763)*(x - 1.88581929876693))^2

u=-3/4*(x + 1)*(x - 2)*x*e^(3/4*(x + 1)*(x - 2)*x) + 1/4*(x + 1)*(x - 2)*x*e^(-1/4*(x + 1)*(x - 2)*x) - 1/6*(x - 1)*(x - 2)*x*e^(1/6*(x - 1)*(x - 2)*x)




asw=sum(f,x,(-1/1),(2/1))#Chevy
ert=numerical_approx(sum(g,x,-1,2/1))#e^-x
cvb=sum(h,x,-1/1,2/1)#Leg
plm=sum(u,x,-1,2/1)#Uni

l2C=norm(vector([ert-asw]))
l2L=norm(vector([ert-cvb]))
l2O=norm(vector([ert-plm]))

l2E=norm(vector([ert]))

linfC=abs(max([asw]))
linfL=abs(max([cvb]))
linfO=abs(max([plm]))
linfE=abs(max([ert]))







l2C
l2L
l2O



linfC
linfL
linfO

1.37065555196861
1.39852837567751
sqrt((1/2*(e^2 - 2*e^(1/2) - 3)*e^(-3/2) + 8.54270702105600)^2)
9.913362573024607
9.941235396733509
1/2*abs(e^2 - 2*e^(1/2) - 3)*e^(-3/2)

var("x")
OP0=-1
OP1=0
OP2=1
OP3=2

ONUME0=(x-OP1)*(x-OP2)*(x-OP3)
ONUME1=(x-OP0)*(x-OP2)*(x-OP3)
ONUME2=(x-OP0)*(x-OP1)*(x-OP3)
ONUME3=(x-OP0)*(x-OP1)*(x-OP3)

ODENO0=(OP0-OP1)*(OP0-OP2)*(OP0-OP3)
ODENO1=(OP1-OP0)*(OP1-OP2)*(OP1-OP3)
ODENO2=(OP2-OP0)*(OP2-OP1)*(OP2-OP3)
ODENO3=(OP3-OP0)*(OP3-OP1)*(OP3-OP2)

OCLagr0=(ONUME0/ODENO0)
OCLagr1=(ONUME1/ODENO1)
OCLagr2=(ONUME2/ODENO2)
OCLagr3=(ONUME3/ODENO3)

Op0=(e^(-OP0))
Op1=(e^(-OP1))
Op2=(e^(-OP2))
Op3=(e^(-OP3))



Uniformly=((Op0*OCLagr0)+(OP1*OCLagr1)+(Op2*OCLagr2)+(Op3*OCLagr3))

x

Uniformly

-1/6*(x - 1)*(x - 2)*x*e - 1/2*(x + 1)*(x - 2)*x*e^(-1) + 1/6*(x + 1)*(x - 2)*x*e^(-2)

plot(Uniformly,(-1,2))+plot(e^(-x),-1,2,color="red")

OP0=-1
OP1=0
OP2=1
OP3=2

ONUME0=(x-OP1)*(x-OP2)*(x-OP3)
ONUME1=(x-OP0)*(x-OP2)*(x-OP3)
ONUME2=(x-OP0)*(x-OP1)*(x-OP3)
ONUME3=(x-OP0)*(x-OP1)*(x-OP3)

ODENO0=(OP0-OP1)*(OP0-OP2)*(OP0-OP3)
ODENO1=(OP1-OP0)*(OP1-OP2)*(OP1-OP3)
ODENO2=(OP2-OP0)*(OP2-OP1)*(OP2-OP3)
ODENO3=(OP3-OP0)*(OP3-OP1)*(OP3-OP2)

OCLagr0=(ONUME0/ODENO0)
OCLagr1=(ONUME1/ODENO1)
OCLagr2=(ONUME2/ODENO2)
OCLagr3=(ONUME3/ODENO3)

Op0=(e^(-OP0))
Op1=(e^(-OP1))
Op2=(e^(-OP2))
Op3=(e^(-OP3))



Uniformly=((Op0*OCLagr0)+(OP1*OCLagr1)+(Op2*OCLagr2)+(Op3*OCLagr3))



#Lagrange Cheveyshev

a=-1
b=2
n=3



i0=0
i1=1
i2=2
i3=3

A=((a+b)/2)
B=((b-a)/2)
E=(e^(-x))

C0= numerical_approx(cos((pi)*((2*i0+1)/(2*n+2))))
C1= numerical_approx(cos((pi)*((2*i1+1)/(2*n+2))))
C2= numerical_approx(cos((pi)*((2*i2+1)/(2*n+2))))
C3= numerical_approx(cos((pi)*((2*i3+1)/(2*n+2))))


CV0=((B*C0)+A)
CV1=((B*C1)+A)
CV2=((B*C2)+A)
CV3=((B*C3)+A)


xo=CV0
xi=CV1
xii=CV2
xiii=CV3


NUME0=(x-xi)*(x-xii)*(x-xiii)
NUME1=(x-xo)*(x-xii)*(x-xiii)
NUME2=(x-xo)*(x-xi)*(x-xiii)
NUME3=(x-xo)*(x-xi)*(x-xii)

DENO0=(xo-xi)*(xo-xii)*(xo-xiii)
DENO1=(xi-xo)*(xi-xii)*(xi-xiii)
DENO2=(xii-xo)*(xii-xi)*(xii-xiii)
DENO3=(xiii-xo)*(xiii-xi)*(xiii-xii)

CLagr0=(NUME0/DENO0)
CLagr1=(NUME1/DENO1)
CLagr2=(NUME2/DENO2)
CLagr3=(NUME3/DENO3)



P0=numerical_approx(e^(-(C0)))
P1=numerical_approx(e^(-(C1)))
P2=numerical_approx(e^(-(C2)))
P3=numerical_approx(e^(-(C3)))

F0=P0*CLagr0
F1=P1*CLagr1
F2=P2*CLagr2
F3=P3*CLagr3



Chevyshev=F0+F1+F2+F3


##Legendre

LP0=1
LP1=x
LP2=(1/2)*(3*((x)^2)-1)
LP3=(((1/2)*(((5)*x^2)-((3)*x))))
LP4=((1/8)*(((35)*x^4)-((30)*x^2)+3))

f=7*LP0
g=8*LP4
h=20*LP2
j=3*LP1
k=2*LP3

solve(LP4,x)

X1=numerical_approx(-sqrt(2/35*sqrt(30) + 3/7))
X2=numerical_approx(sqrt(2/35*sqrt(30) + 3/7))
X3=numerical_approx(-sqrt(-2/35*sqrt(30) + 3/7))
X4=numerical_approx(sqrt(-2/35*sqrt(30) + 3/7))


LOV0=((B*X1)+A)
LOV1=((B*X2)+A)
LOV2=((B*X3)+A)
LOV3=((B*X4)+A)

lxo=LOV0
lxi=LOV1
lxii=LOV2
lxiii=LOV3


LNUME0=(x-lxi)*(x-lxii)*(x-lxiii)
LNUME1=(x-lxo)*(x-lxii)*(x-lxiii)
LNUME2=(x-lxo)*(x-lxi)*(x-lxiii)
LNUME3=(x-lxo)*(x-lxi)*(x-lxii)

LDENO0=(lxo-lxi)*(lxo-lxii)*(lxo-lxiii)
LDENO1=(lxi-lxo)*(lxi-lxii)*(lxi-lxiii)
LDENO2=(lxii-lxo)*(lxii-lxi)*(lxii-lxiii)
LDENO3=(lxiii-lxo)*(lxiii-lxi)*(lxiii-lxii)

LLagr0=(LNUME0/LDENO0)
LLagr1=(LNUME1/LDENO1)
LLagr2=(LNUME2/LDENO2)
LLagr3=(LNUME3/LDENO3)


LP0=numerical_approx(e^(-(X1)))
LP1=numerical_approx(e^(-(X2)))
LP2=numerical_approx(e^(-(X3)))
LP3=numerical_approx(e^(-(X4)))

LF0=LP0*LLagr0
LF1=LP1*LLagr1
LF2=LP2*LLagr2
LF3=LP3*LLagr3

Legendere=LF0+LF1+LF2+LF3




f = (0.116167595984182*(x + 0.791704467391079)*(x + 0.00997156537728427)*(x - 1.00997156537728) - 0.495492470126893*(x + 0.791704467391079)*(x + 0.00997156537728427)*(x - 1.79170446739108) + 0.978004473650812*(x + 0.791704467391079)*(x - 1.00997156537728)*(x - 1.79170446739108) - 0.650217267384311*(x + 0.00997156537728427)*(x - 1.00997156537728)*(x - 1.79170446739108))^2

g=(e^-x)^2

h=(0.0900243711092997*(x + 0.885819298766930)*(x + 0.0740251485476346)*(x - 1.07402514854763) - 0.373399955130276*(x + 0.885819298766930)*(x + 0.0740251485476346)*(x - 1.88581929876693) + 0.802728841958563*(x + 0.885819298766930)*(x - 1.07402514854763)*(x - 1.88581929876693) - 0.571257167284918*(x + 0.0740251485476346)*(x - 1.07402514854763)*(x - 1.88581929876693))^2

u=-3/4*(x + 1)*(x - 2)*x*e^(3/4*(x + 1)*(x - 2)*x) + 1/4*(x + 1)*(x - 2)*x*e^(-1/4*(x + 1)*(x - 2)*x) - 1/6*(x - 1)*(x - 2)*x*e^(1/6*(x - 1)*(x - 2)*x)




asw=sum(f,x,(-1/1),(2/1))#Chevy
ert=numerical_approx(sum(g,x,-1,2/1))#e^-x
cvb=sum(h,x,-1/1,2/1)#Leg
plm=sum(u,x,-1,2/1)#Uni

l2C=norm(vector([ert-asw]))
l2L=norm(vector([ert-cvb]))
l2O=norm(vector([ert-plm]))

l2E=norm(vector([ert]))

linfC=abs(max([asw]))
linfL=abs(max([cvb]))
linfO=abs(max([plm]))
linfE=abs(max([ert]))







l2C
l2L
l2O



linfC
linfL
linfO









Chevyshev



Uniformly


Legendere
plot(Legendere)
l2L
linfL

print'The first root is %s'%X1
print'The second root is %s'%X2
print'The third root is %s'%X3
print'The forth root is %s'%X4



Chevyshev
plot(Chevyshev)
l2C
linfC

print'The first Chevyshev point is %s'%CV0
print'The second Chevyshev point is %s'%CV1
print'The third Chevyshev point is %s'%CV2
print'The forth Chevyshev point is %s'%CV3




Uniformly
plot(Uniformly)
l2O
linfO

[x == -sqrt(2/35*sqrt(30) + 3/7), x == sqrt(2/35*sqrt(30) + 3/7), x == -sqrt(-2/35*sqrt(30) + 3/7), x == sqrt(-2/35*sqrt(30) + 3/7)]
1.37065555196861
1.39852837567751
sqrt((1/2*(e^2 - 2*e^(1/2) - 3)*e^(-3/2) + 8.54270702105600)^2)
9.913362573024607
9.941235396733509
1/2*abs(e^2 - 2*e^(1/2) - 3)*e^(-3/2)
0.0900243711092997*(x + 0.885819298766930)*(x + 0.0740251485476346)*(x - 1.07402514854763) - 0.373399955130276*(x + 0.885819298766930)*(x + 0.0740251485476346)*(x - 1.88581929876693) + 0.802728841958563*(x + 0.885819298766930)*(x - 1.07402514854763)*(x - 1.88581929876693) - 0.571257167284918*(x + 0.0740251485476346)*(x - 1.07402514854763)*(x - 1.88581929876693)
-1/6*(x - 1)*(x - 2)*x*e - 1/2*(x + 1)*(x - 2)*x*e^(-1) + 1/6*(x + 1)*(x - 2)*x*e^(-2)
0.116167595984182*(x + 0.791704467391079)*(x + 0.00997156537728427)*(x - 1.00997156537728) - 0.495492470126893*(x + 0.791704467391079)*(x + 0.00997156537728427)*(x - 1.79170446739108) + 0.978004473650812*(x + 0.791704467391079)*(x - 1.00997156537728)*(x - 1.79170446739108) - 0.650217267384311*(x + 0.00997156537728427)*(x - 1.00997156537728)*(x - 1.79170446739108)

1.39852837567751
9.941235396733509
The first root is -0.861136311594053
The second root is 0.861136311594053
The third root is -0.339981043584856
The forth root is 0.339981043584856
0.0900243711092997*(x + 0.885819298766930)*(x + 0.0740251485476346)*(x - 1.07402514854763) - 0.373399955130276*(x + 0.885819298766930)*(x + 0.0740251485476346)*(x - 1.88581929876693) + 0.802728841958563*(x + 0.885819298766930)*(x - 1.07402514854763)*(x - 1.88581929876693) - 0.571257167284918*(x + 0.0740251485476346)*(x - 1.07402514854763)*(x - 1.88581929876693)

1.37065555196861
9.913362573024607
The first Chevyshev point is 1.88581929876693
The second Chevyshev point is 1.07402514854763
The third Chevyshev point is -0.0740251485476346
The forth Chevyshev point is -0.885819298766930
-1/6*(x - 1)*(x - 2)*x*e - 1/2*(x + 1)*(x - 2)*x*e^(-1) + 1/6*(x + 1)*(x - 2)*x*e^(-2)

sqrt((1/2*(e^2 - 2*e^(1/2) - 3)*e^(-3/2) + 8.54270702105600)^2)
1/2*abs(e^2 - 2*e^(1/2) - 3)*e^(-3/2)

#want 200 equally spaced points from -1 to 2
delta=(2-(-1))/200

points = [-1+i*delta.n(digits=3) for i in range(0,200)]

points

[-1.00, -0.985, -0.970, -0.955, -0.940, -0.925, -0.910, -0.895, -0.880, -0.865, -0.850, -0.835, -0.820, -0.805, -0.790, -0.775, -0.760, -0.745, -0.730, -0.715, -0.700, -0.685, -0.670, -0.655, -0.640, -0.625, -0.610, -0.595, -0.580, -0.565, -0.550, -0.535, -0.520, -0.505, -0.490, -0.475, -0.460, -0.445, -0.430, -0.415, -0.400, -0.385, -0.370, -0.355, -0.340, -0.325, -0.310, -0.295, -0.280, -0.265, -0.250, -0.235, -0.220, -0.205, -0.190, -0.175, -0.160, -0.145, -0.130, -0.115, -0.100, -0.0850, -0.0700, -0.0550, -0.0400, -0.0250, -0.00995, 0.00500, 0.0200, 0.0350, 0.0500, 0.0651, 0.0801, 0.0950, 0.110, 0.125, 0.140, 0.155, 0.170, 0.185, 0.200, 0.215, 0.230, 0.245, 0.260, 0.275, 0.290, 0.305, 0.320, 0.335, 0.350, 0.365, 0.380, 0.395, 0.410, 0.425, 0.440, 0.455, 0.470, 0.485, 0.500, 0.515, 0.530, 0.545, 0.560, 0.575, 0.590, 0.605, 0.620, 0.635, 0.650, 0.665, 0.680, 0.695, 0.710, 0.725, 0.740, 0.755, 0.770, 0.785, 0.800, 0.815, 0.830, 0.845, 0.860, 0.875, 0.890, 0.905, 0.920, 0.935, 0.950, 0.965, 0.980, 0.995, 1.01, 1.03, 1.04, 1.05, 1.07, 1.08, 1.10, 1.11, 1.13, 1.15, 1.16, 1.18, 1.19, 1.21, 1.22, 1.24, 1.25, 1.27, 1.28, 1.30, 1.31, 1.32, 1.34, 1.35, 1.37, 1.39, 1.40, 1.42, 1.43, 1.45, 1.46, 1.48, 1.49, 1.51, 1.52, 1.54, 1.55, 1.56, 1.58, 1.59, 1.61, 1.62, 1.64, 1.66, 1.67, 1.69, 1.70, 1.72, 1.73, 1.75, 1.76, 1.78, 1.79, 1.81, 1.82, 1.83, 1.85, 1.86, 1.88, 1.90, 1.91, 1.93, 1.94, 1.96, 1.97, 1.99]

type(points[1])

<type 'sage.rings.real_mpfr.RealNumber'>

pp=points[1]

pp.n(prec=10)

-0.99

delta.n()


abs

0.0150000000000000
<built-in function abs>

L=[3,4,5]
L2norm_of_l=sqrt(sum([x^2 for x in L]))

max(L)

5

L2norm_of_l

5*sqrt(2)

norm?

File: /projects/sage/sage-6.10/local/lib/python2.7/site-packages/sage/misc/functional.py
Signature : norm()
Docstring :
Returns the norm of "x".

For matrices and vectors, this returns the L2-norm. The L2-norm of
a vector *v* = (v_1, v_2, ..., v_n), also called the Euclidean
norm, is defined as

   |*v*| = sqrt{sum_{i=1}^n |v_i|^2}

where |v_i| is the complex modulus of v_i. The Euclidean norm is
often used for determining the distance between two points in two-
or three-dimensional space.

For complex numbers, the function returns the field norm. If c = a
+ bi is a complex number, then the norm of c is defined as the
product of c and its complex conjugate

   norm(c) = norm(a + bi) = c  * overline{c} = a^2 + b^2.

The norm of a complex number is different from its absolute value.
The absolute value of a complex number is defined to be the square
root of its norm. A typical use of the complex norm is in the
integral domain ZZ[i] of Gaussian integers, where the norm of each
Gaussian integer c = a + bi is defined as its complex norm.

See also: * "sage.matrix.matrix2.Matrix.norm()"


  * "sage.modules.free_module_element.FreeModuleElement.norm()"

  * "sage.rings.complex_double.ComplexDoubleElement.norm()"

  * "sage.rings.complex_number.ComplexNumber.norm()"

  * "sage.symbolic.expression.Expression.norm()"

EXAMPLES:

The norm of vectors:

   sage: z = 1 + 2*I
   sage: norm(vector([z]))
   sqrt(5)
   sage: v = vector([-1,2,3])
   sage: norm(v)
   sqrt(14)
   sage: _ = var("a b c d", domain='real')
   sage: v = vector([a, b, c, d])
   sage: norm(v)
   sqrt(a^2 + b^2 + c^2 + d^2)

The norm of matrices:

   sage: z = 1 + 2*I
   sage: norm(matrix([[z]]))
   2.23606797749979
   sage: M = matrix(ZZ, [[1,2,4,3], [-1,0,3,-10]])
   sage: norm(M)  # abs tol 1e-14
   10.690331129154467
   sage: norm(CDF(z))
   5.0
   sage: norm(CC(z))
   5.00000000000000

The norm of complex numbers:

   sage: z = 2 - 3*I
   sage: norm(z)
   13
   sage: a = randint(-10^10, 100^10)
   sage: b = randint(-10^10, 100^10)
   sage: z = a + b*I
   sage: bool(norm(z) == a^2 + b^2)
   True

The complex norm of symbolic expressions:

   sage: a, b, c = var("a, b, c")
   sage: assume((a, 'real'), (b, 'real'), (c, 'real'))
   sage: z = a + b*I
   sage: bool(norm(z).simplify() == a^2 + b^2)
   True
   sage: norm(a + b).simplify()
   a^2 + 2*a*b + b^2
   sage: v = vector([a, b, c])
   sage: bool(norm(v).simplify() == sqrt(a^2 + b^2 + c^2))
   True
   sage: forget()

solns=solve(x^2==1,x)

type(solns)

<class 'sage.structure.sequence.Sequence_generic'>

solns

[x == -1, x == 1]

list(solns)

[x == -1, x == 1]

solns[0]

x == -1

type(solns[0])

<type 'sage.symbolic.expression.Expression'>

solns[0].rhs()

-1

[solns[x].rhs() for x in range(0,len(solns))]

[-1, 1]