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I am trying to get the following function, to plot with a log y axis. However, when I replace Plot with LogPlot, the plot is not computed correctly. Instead, a plot with incorrect x-axis is returned.

Constants

au = QuantityMagnitude[UnitConvert[Quantity[1, "AstronomicalUnit"], "Meters"]]; 
c = QuantityMagnitude[UnitConvert[Quantity[1, "SpeedOfLight"], "MetersPerSecond"]]; 
Qpr = 1; 
Lsun = QuantityMagnitude[UnitConvert[Quantity[1, "SolarLuminosity"], "Watts"]]; 
Rsun = QuantityMagnitude[UnitConvert[Quantity[1, "SolarRadius"], "Meters"]]; 
Msun = QuantityMagnitude[UnitConvert[Quantity[1, "SolarMass"], "Kilograms"]]; 
G = QuantityMagnitude[UnitConvert[Quantity[1, "GravitationalConstant"], ("Meters"^2*"Newtons")/"Kilograms"^2]]; 
year = QuantityMagnitude[UnitConvert[Quantity[1, "Years"], "Seconds"]]; 
Myr = year*10^6; 
Gyr = year*10^9; 
Mwd = 0.6*Msun; 
Cst = 1.27; 
U = 1*10^17; 

Functions

L[t_] := (3.26*Lsun*(Mwd/(0.6*Msun)))/(0.1 + t/Myr)^1.18; 
Roche[dens_] := (0.65*Cst*Rsun*(Mwd/(0.6*Msun))^(1/3))/(dens/3000)^3^(-1); 
Papsis[t_] := a[t]*(1 - e[t]); 

Radiative Drag

RDdadtR\[Rho]a = -((3*L[t]*Qpr*(2 + 3*e[t]^2))/(c^2*(16*Pi*\[Rho]*Rast*a[t]*(1 - e[t]^2)^(3/2)))); 
RDdedtR\[Rho]a = -((15*L[t]*e[t])/(c^2*(32*Pi*Rast*\[Rho]*a[t]^2*Sqrt[1 - e[t]^2]))); 

RDsolR\[Rho]a = ParametricNDSolveValue[{Derivative[1][a][t] == RDdadtR\[Rho]a, Derivative[1][e][t] == RDdedtR\[Rho]a, a[0] == a0, e[0] == 0.3}, {a, e}, {t, 0, 9*Gyr}, 
    {Rast, \[Rho], a0}]; 

fRDticks = {{Automatic, Automatic}, {Charting`FindTicks[{0, 1}, {0, 1/Myr}], Automatic}}; 

Manipulate[Column[{Style["Radiative Drag Working Plot", Bold], Plot[fun[func, t]/scale[func], {t, 0, 9*Gyr}, FrameTicks -> fRDticks, 
     Epilog -> {Red, Dashed, InfiniteLine[{{0, Roche[\[Rho]]}, {10, Roche[\[Rho]]}}]}, PlotStyle -> {Directive[Blue, Thickness[0.01]]}], Style["Compiled Plot", Bold], 
    If[comp === {}, Plot[fun[func, t]/scale[func], {t, 0, 9*Gyr}, FrameTicks -> fRDticks, Epilog -> {Red, Dashed, InfiniteLine[{{0, Roche[\[Rho]]}, {10, Roche[\[Rho]]}}]}, 
      PlotStyle -> {Directive[Blue, Thickness[0.01]]}], Plot[comp/scale[func], {t, 0, 9*Gyr}, FrameTicks -> fRDticks, 
      Epilog -> {Red, Dashed, InfiniteLine[{{0, Roche[\[Rho]]}, {10, Roche[\[Rho]]}}]}, PlotStyle -> {Directive[Blue, Thickness[0.01]]}]]}], 
  {{func, 1}, {1 -> "a", 2 -> "e", 3 -> "q"}}, {{Rast, 0.005}, 0.0001, 0.1, 0.001, Appearance -> "Labeled"}, {{\[Rho], 3000}, 1000, 7000, 50, Appearance -> "Labeled"}, 
  {{a0, 10, "a0 (au)"}, 1, 20, 0.2, Appearance -> "Labeled"}, Button["Append", AppendTo[comp, fun[func, t]]], Button["Reset", comp = {}], 
  TrackedSymbols -> {func, Rast, \[Rho], a0}, Initialization :> {comp = {}, fun[sel_, t_] := Switch[sel, 1, RDsolR\[Rho]a[Rast, \[Rho], a0*au][[1]][t], 2, 
      RDsolR\[Rho]a[Rast, \[Rho], a0*au][[2]][t], 3, RDsolR\[Rho]a[Rast, \[Rho], a0*au][[1]][t]*(1 - RDsolR\[Rho]a[Rast, \[Rho], a0*au][[2]][t])], 
    scale[sel_] := Switch[sel, 1 | 3, au, 2, 1]}]

The question is- how do I get this plot to have a logarithmic y axis?

Thanks in advance.

EDIT: enter image description here

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8
  • $\begingroup$ Your function changes very little. Therefore, a log axis looks similar to a linear axis. $\endgroup$ – Daniel Huber Feb 16 at 15:02
  • $\begingroup$ @DanielHuber I still need a log axis as I'm going to be changing the parameter values such that the y axis will change quickly. LogPlot completely changes the graph and so I don't think it's the correct solution. $\endgroup$ – testing09 Feb 16 at 15:07
  • $\begingroup$ I can not see much of a difference when I change Plot and LogPlot. Can you give an example about what you mean? $\endgroup$ – Daniel Huber Feb 16 at 15:21
  • $\begingroup$ @DanielHuber I've added a picture above. $\endgroup$ – testing09 Feb 16 at 17:51
  • $\begingroup$ But your plot have very little y change. In this case a log plot looks like a linear plot $\endgroup$ – Daniel Huber Feb 16 at 19:14
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au = QuantityMagnitude[
   UnitConvert[Quantity[1, "AstronomicalUnit"], "Meters"]];
c = QuantityMagnitude[
   UnitConvert[Quantity[1, "SpeedOfLight"], "MetersPerSecond"]];
Qpr = 1;
Lsun = QuantityMagnitude[
   UnitConvert[Quantity[1, "SolarLuminosity"], "Watts"]];
Rsun = QuantityMagnitude[
   UnitConvert[Quantity[1, "SolarRadius"], "Meters"]];
Msun = QuantityMagnitude[
   UnitConvert[Quantity[1, "SolarMass"], "Kilograms"]];
G = QuantityMagnitude[
   UnitConvert[
    Quantity[1, "GravitationalConstant"], ("Meters"^2*"Newtons")/
     "Kilograms"^2]];
year = QuantityMagnitude[UnitConvert[Quantity[1, "Years"], "Seconds"]];
Myr = year*10^6;
Gyr = year*10^9;
Mwd = 0.6*Msun;
Cst = 1.27;
U = 1*10^17;


L[t_] := (3.26*Lsun*(Mwd/(0.6*Msun)))/(0.1 + t/Myr)^1.18;
Roche[dens_] := (0.65*Cst*
     Rsun*(Mwd/(0.6*Msun))^(1/3))/(dens/3000)^3^(-1);
Papsis[t_] := a[t]*(1 - e[t]);



RDdadtR\[Rho]a = -((3*L[t]*
       Qpr*(2 + 3*e[t]^2))/(c^2*(16*Pi*\[Rho]*Rast*
         a[t]*(1 - e[t]^2)^(3/2))));
RDdedtR\[Rho]a = -((15*L[t]*
       e[t])/(c^2*(32*Pi*Rast*\[Rho]*a[t]^2*Sqrt[1 - e[t]^2])));

RDsolR\[Rho]a = 
  ParametricNDSolveValue[{Derivative[1][a][t] == RDdadtR\[Rho]a, 
    Derivative[1][e][t] == RDdedtR\[Rho]a, a[0] == a0, 
    e[0] == 0.3}, {a, e}, {t, 0, 9*Gyr}, {Rast, \[Rho], a0}];

fRDticks = {{Automatic, 
    Automatic}, {Charting`FindTicks[{0, 1}, {0, 1/Myr}], Automatic}};

Manipulate[
 Column[{Style["Radiative Drag Working Plot", Bold], 
   LogPlot[fun[func, t]/scale[func], {t, 0, 9*Gyr}, 
    FrameTicks -> fRDticks, 
    Epilog -> {Red, Dashed, 
      InfiniteLine[{{0, Roche[\[Rho]]}, {10, Roche[\[Rho]]}}]}, 
    PlotStyle -> {Directive[Blue, Thickness[0.01]]}], 
   Style["Compiled Plot", Bold], 
   If[comp === {}, 
    LogPlot[fun[func, t]/scale[func], {t, 0, 9*Gyr}, 
     FrameTicks -> fRDticks, 
     Epilog -> {Red, Dashed, 
       InfiniteLine[{{0, Roche[\[Rho]]}, {10, Roche[\[Rho]]}}]}, 
     PlotStyle -> {Directive[Blue, Thickness[0.01]]}], 
    LogPlot[comp/scale[func], {t, 0, 9*Gyr}, FrameTicks -> fRDticks, 
     Epilog -> {Red, Dashed, 
       InfiniteLine[{{0, Roche[\[Rho]]}, {10, Roche[\[Rho]]}}]}, 
     PlotStyle -> {Directive[Blue, Thickness[0.01]]}]]}], {{func, 
   1}, {1 -> "a", 2 -> "e", 3 -> "q"}}, {{Rast, 0.005}, 0.0001, 0.1, 
  0.001, Appearance -> "Labeled"}, {{\[Rho], 3000}, 1000, 7000, 50, 
  Appearance -> "Labeled"}, {{a0, 10, "a0 (au)"}, 1, 20, 0.2, 
  Appearance -> "Labeled"}, 
 Button["Append", AppendTo[comp, fun[func, t]]], 
 Button["Reset", comp = {}], 
 TrackedSymbols -> {func, Rast, \[Rho], a0}, 
 Initialization :> {comp = {}, 
   fun[sel_, t_] := 
    Switch[sel, 1, RDsolR\[Rho]a[Rast, \[Rho], a0*au][[1]][t], 2, 
     RDsolR\[Rho]a[Rast, \[Rho], a0*au][[2]][t], 3, 
     RDsolR\[Rho]a[Rast, \[Rho], a0*au][[1]][
       t]*(1 - RDsolR\[Rho]a[Rast, \[Rho], a0*au][[2]][t])], 
   scale[sel_] := Switch[sel, 1 | 3, au, 2, 1]}]
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2
  • $\begingroup$ the x-axis has changed from Myr to seconds. $\endgroup$ – testing09 Feb 16 at 19:44
  • $\begingroup$ Where is the difference? $\endgroup$ – Daniel Huber Feb 16 at 20:00

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