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Gin (guest) 16 May 2018 06:52
in discussion DDSCAT / General discussion » Error: bash - ddscat: command not found

I have the same problem with Amey when using version 7.3.2. I copied ddscat from ../src/ddscat to the folder of the example but still got the error "command not found" in the .log file (or .out file). Hence I guess the command of "make ddscat" might not success when producing these below lines (just the tail of compiling process). Could you say if it completes the compilation? What wrong with running the examples?

gfortran -c -O2 writefml.f90 -o writefml.o
gfortran -c -O2 writepol.f90 -o writepol.o
gfortran -c -O2 writesca.f90 -o writesca.o
gfortran -c -O2 zbcg2wp.f90 -o zbcg2wp.o
LOADEDMODULES=
LOADEDMODULES_modshare=
LD_LIBRARY_PATH=
LD_LIBRARY_PATH_modshare=
MKLROOT=
CPATH=
FPATH=
DYLD_LIBRARY_PATH=
INCLUDE=
LIBRARY_PATH=
gfortran -o ddscat DDSCAT.o alphadiag.o blas.o bself.o ccgpack.o cgcommon.o cglib2.o cglib3.o cgsarkar2.o cgsarkar3.o cisi.o copyit.o cprod.o cxfft3n.o cxfft3_mkl_fake.o cxfftw_fake.o ddcommon.o dielec.o direct_calc.o direct_calcb.o divide.o dsyevj3.o dummy.o errmsg.o eself.o evala.o evale.o evalq.o extend.o gasdev.o getfml.o getmueller.o gpbicg.o gpfa.o interp.o mpi_fake.o namer.o namer2.o namid.o nearfield.o nuller.o orient.o p_lm.o pad.o pbcscavec.o pim.o prinaxis.o qmrpim2.o ran3.o reapar.o reashp.o reduce.o restore.o rot2.o rotate.o scat.o scavec.o tangcg.o tar2el.o tar2sp.o tar3el.o taranirec.o tarblocks.o tarcel.o tarcyl.o tarcylcap.o tarell.o target.o targspher.o tarhex.o tarlyrslab.o tarnas.o tarnsp.o taroct.o taronion.o tarpbxn.o tarprsm.o tarrctblk3.o tarrctell.o tarrec.o tarrecrec.o tarslbhol.o tartet.o timeit.o unreduce.o version.o wrimsg.o writebin.o writefml.o writepol.o writesca.o zbcg2wp.o
[gin@starbucks src]$

by Gin (guest), 16 May 2018 06:52

If the two plane wave sources are incoherent, then the scattered power, absorbed power, forces, and torques, can be obtained by simply summing the results calculated for single plane waves from the appropriate directions.
If the two plane wave sources are coherent (with one another) then the problem is more complicated. Subroutine EVALE (evale.f90) can be modified to provide whatever incident wave is desired, but a number of other modifications would be required to pass parameters to EVALE, and the total extinction cross section can no longer be evaluated using the optical theorem as DDSCAT does now.

I am a very new user of DDSCAT, I am primarily interested in nearfield calculations and scattering forces on spherical particles. It would be very useful if there was an ability to also calculate these under two planewave sources each with their own propagation direction. Does DDSCAT support this type of calculation? If not, does anyone have any advice for me if I wish to get this done? (i.e. is there another code that already does this, or is it possible to make simple modifications to pre-existing code).

Thanks in advance!

Please switch to DDSCAT 7.3.2 !! DDSCAT 7.1 is no longer supported.

In Gaussian ("cgs") electromagnetism, polarizability has dimensions of volume. DDSCAT reports alpha/d^3, where d is the lattice spacing; i.e., alpha is given in units of d^3.

Dipole polarizations P_j = alpha_j*E_j are given in units of d^3 multiplied by whatever units you consider the electric field to be measured in when you specify the value of the incident E field in ddscat.par

Re: Polarization vectors by drainedraine, 18 Apr 2018 18:09
Polarization vectors
Claire (guest) 18 Apr 2018 17:51
in discussion DDSCAT / General discussion » Polarization vectors

Hi, I am running DDSCAT7.1 and I can print the wxxxryyykzzz.pol1 in a (human) readable form. However I'm not sure what the units are for the numbers I am outputting. I assume they're unitless and probably normalized to the incident electric field, but what about alpha? Is alpha normalized somehow?

Polarization vectors by Claire (guest), 18 Apr 2018 17:51
Tadele (guest) 27 Mar 2018 10:27
in discussion DDSCAT / General discussion » Error in code when running for CONELLIPS target.

Dear sir,

I am planning to do so many calculations using ddscat7.3.2, but it seems I am having a problem from the beginning.

I am using UBUNTU and I have followed the steps stated in the user guide from downloading the source code (section 5) to running the program (subsection 10.1) but I suspect that I am missing something. While being in RCTGLPRSM, I have changed the vacume wavelength to " 0.700 0.700 1 'LIN' " and I have created the symbolic link as per the instruction in section 10.1. However, when I perform the calculation using "ddscat >& ddscat.out &" , my terminal goes away (disappears) and I don't see any changes on the values of Q_scat, Q_ext… in the qtable.sav file. In the ddscat.par file

My ddscat.out file says "NO command 'ddscat' found, did you mean:
command 'ddscat' from package 'ptscotch' (universal)
ddscat: command not found "

Thank you,
Tadele

by Tadele (guest), 27 Mar 2018 10:27
Aggregates
hirakhirak 05 Mar 2018 08:19
in discussion DDSCAT / General discussion » Aggregates

Hello Everyone,
I have modelled a group of nanospheres grouped together almost in a straight line. Can I model the scattering properties such that results obtained from the first nanosphere would become an input for the second nanosphere and so on for the whole network?
Thanks,
Hirak

Aggregates by hirakhirak, 05 Mar 2018 08:19

Hi, I've compiled the ddscat with MPI enabled. When I run it, only one core's usage reaches 100% & rest of the cores usage is around 10%. In case of OpenMP, I use the OMP_NUM_THREADS variable to fix the thread number. However, in case of MPI, I don't know how to choose the number of cores.

I'm running the code in Linux Mint platform. The computer has 16GB RAM, 8 cores & I also installed 'OpenMPI.' Please kindly help me.

Thanks

How to choose number of cores? by Prasanth (guest), 22 Feb 2018 11:46
Pradeep Bhatia (guest) 19 Feb 2018 12:12
in discussion DDSCAT / General discussion » Error in code when running for CONELLIPS target.

in our case, shell thickness is 0.5d and number of dipoles ~ 4840 dipoles. We took the d ~ 2 , when setting the physical size i.e. N*d^3 = (4*pi/3)aeff^3. after putting the N = 4840 dipoles and d ~ 2 and the we find out the affective radius i.e. ~ 20 nm. So in case shell thickness will be 0.5*2 = 1 nm.
Sir, am i right ?
Thanking You.

by Pradeep Bhatia (guest), 19 Feb 2018 12:12

The ddscat.par parameters 21 21 21 20 20 20 specify a target with outer sphere diameter 21d and inner diameter 20d (*not* 21nm and 20nm unless you happen to have d=1nm). A sphere with diameter 21d has N approx (4*pi/3)*(10.5)^3 approx 4800 dipoles. The shell thickness would be 10.5d-10d=0.5d.

The effective radius aeff (in physical units) is specified on a separate line of ddscat.par . The physical size of
d is then fixed by N*d^3=(4*pi/3)aeff^3 , where N is the total number of non-vacuum dipoles.

Please consult the UserGuide for further details.

by drainedraine, 16 Feb 2018 16:49
Pradeep Bhatia (guest) 16 Feb 2018 06:06
in discussion DDSCAT / General discussion » Error in code when running for CONELLIPS target.

Dear Sir,
I have one more problem regarding the core-shell calculations, when we define the outer and inner size e.g. 21 21 21 20 20 20, it means that, there is 1 nm shell thickness with core size 20 nm. while we defining such parameter, these parameters also defining the dipole, So for this condition, the number of dipoles must be 10 ^ 4. But in our above considered case, the dipoles are very less ( 4 x 10 ^ 3) . therefore, i want to know that how we can define the relevance dipoles and effective size (radius) ?
I am waiting yours fruitful discussion.
I wish you ll reply as soon as possible.
Thanking You

by Pradeep Bhatia (guest), 16 Feb 2018 06:06

1. specifiying the outer (70d) and inner (30d) diameters obviously determines the thickness of the shell (20d).
2. if ddscat terminated without writing Q values into qtable, then it didn't terminate normally.
I suggest you examine whatever was written to "standard output" to determine the reason for the code terminated.

Pradeep Bhatia (guest) 15 Feb 2018 16:41
in discussion DDSCAT / General discussion » Error in code when running for CONELLIPS target.

Daer Sir,
I have one more problem regarding the core-shell calculations, when we define the outer and inner size e.g. 21 21 21 20 20 20, it means that, there is 1 nm shell thickness with core size 20 nm. while we defining such parameter, these parameters also defining the dipole, So for this condition, the number of dipoles must be 10 ^ 4. But in our above considered case, the dipoles are very less ( 4 x 10 ^ 3) . therefore, i want to know that how we can define the relevance dipoles ?
I am waiting yours fruitful discussion.
I wish you ll reply as soon as possible.
Thanking You

by Pradeep Bhatia (guest), 15 Feb 2018 16:41

Dear Sir,
I ran the calculation for Q_scat values for conellips using 70 70 70 30 30 30 shape parameters. The calculation executed with normal termination but no Q_scat or Q_ext values were shown in qtable file.
Moreoever, I am not much clear about the shape parameters. I mean, in my calculations, how to decide the thickness of core and mantle in conellips?

Thanks in advance,

Please consult the UserGuide.
The index shows 2 entries for "effective radius" — pages 9 and 24.
a_{eff}= effective radius is defined by equation 4 on page 9.

Re: effective radii by drainedraine, 06 Feb 2018 13:01

How to calculate the effective radii of a spherical particle (let say 1 nm)? I have checked in the manual but still have doubt on the calculations. can some re post the answer to this?

effective radii by shweta bhardwajshweta bhardwaj, 06 Feb 2018 03:56

As explained in the UserGuide, wxxxryyykzzz.E1 and wxxxryyykzzz.E2 each contain the electric fields
E_sca and E_inc at each point j in the computational volume, where the total E=E_sca+E_inc,
for incident polarizations 1 and 2.

The files wxxxryyykzzz.En are intended to be read by the program DDPOSTPROCESS.f90.
If you compile and run this on the same architecture that was used to run DDSCAT, DDPOSTPROCESS should be able to read the binary files wxxxryyykzzz.En created by DDSCAT.

Please see section 30 of the UserGuide for instructions on using DDPOSTPROCESS.
The user needs to create a file ddpostprocess.par to tell DDPOSTPROCESS what output is desired.
An example of ddpostprocess.par (as well as output files) can be found in examples_exp/ELLIPSOID_NEARFIELD

Dear Sir
I am doing the near-field calculations, as given in user guide of DDSCAT 7.3 on 29, 29.1 & 29.2 sections. when, we calculate the near-field calculation after choosing important parameter i.e. 1 = NRFLD (=0 to skip nearfield calc., =1 for nearfield E, =2 for E and B) and 2 = IORTH (=1 to do only pol. state e01; =2 to also do orth. pol. state), and 1 = IWRKSC (=0 to suppress, =1 to write ".sca" file for each target orient.; After doing these changing in ddscat.par file and run in the ddscat. we got the extra file like w000r000k000.E1 & w000r000k000.E2 and so on….w000r000k000.E200. Till now, i followed these steps.
Now, my Question is how to use .E2, .E2, .E3 and so on .E200 files for further calculation ?
Q1. Is it single point calculation.
Q2. If it is not single point calculation, then how to add these file into E1+E2…….=En
Q3. is it run directly through ddpostprocess or we have to make ddpostprocess.par file. if yes, then How to make and which parameter are use in ddpostprocess.par file. and how to run after preparing the ddpostprocess.par file.
I wish you will reply soon.
Thanking You

Regarding the Near-field Calculations by Pradeep Bhatia (guest), 02 Feb 2018 08:06
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