The Computational Optimization of the Invariant Imbedding T Matrix Method for the Particles with N-Fold Symmetry

Round 1

Reviewer 1 Report

The authors discuss an optimization for the computation of  T matrix for a class of aspherical particles – the ones with N-fold Symmetry – using Invariant Imbedding T matrix method.  The paper is in general clear, but some improvements are needed. English language sometimes needs to be revised and some typos must be corrected. Very often authors use acronyms, but they do not give their definition. Since the paper treats N-fold symmetric particles a clear and extensive definition must be given in the introduction. The same for the method the authors want to improve.

Hereby some comments in detail.

1)     Pag. 2 line 48. change references number and update.

2)     Pag. 2 line 57. DDA, please define the acronym.

3)     Pag. 2 line 58 and 63 IIA and SVM, please define the acronyms.

4)     Pag. 2 lines 66 - 68.  The authors write: “ In recent years, Hu et al. Combined Lorenz Mie scattering theory with invariant imbedding iteration technology, and independently developed the Invariant Imbedding T-matrix model.”. First  insert reference and/or number for Hu et al.  Second change the sentence in order to give a sense to the phrase. Improve English syntax.

5)     Page. 2 lines 72 – 75. The authors affirm: “Although the invariant imbedding T-matrix method has tremendous advantages in non-spherical particle scattering simulation, its computational efficiency is far lower than that of EBCM, the reasons include two aspects: On the one hand, the IIM T-matrix model needs to be iterated layer by layer along the radial direction, the larger the particle size is, the more iterations are required. On the one hand the IIM T-matrix model needs to be iterated layer by layer along the radial direction, the larger the particle size is, the more iterations are required”. Only one aspect is described. Please improve English language and avoid the use on “On the one hand”.

6)     Pag. 2 line 88. The authors affirm: “ …. structure, the T-matrix can be diagonalized into block ones”. Please explain the meaning of the sentence.

7)     Pag. 2 lines 92 - 93. The authors write: “ So we think that can this idea be generalized and applied to the Invariant Imbedding T-matrix method?” Improve English syntax, error in the formulation of the question.

8)     Pag. 4 Line 135. Begin of Paragraph 3: Please give a clear definition of a N-fold symmetric particle, adding also a figure.

9)     Pag. 9 line 211. Use m insted of “u”

10)  Pag. 10 line 238. Since the authors aim to compare results for hexagonal and cotagonal particles, they must explain the reason for changing wavelength and refractive index for T-matrix computation of octagonal prism particles. For hexagonal particles they use a wavelength equal to 500 nm and a refractive index of 1.33+0.0008i, while for octagonal particles they use a wavelength of 1000 nm and a refractive index of 1.23+0.0008i.

11)  Pag. 10 line 239. Use m insted of “u”

12)  Pag. 10 line 243. Replace “more agreement” with “better agreement”.

13)  Pag 10 lines 249 - 253. The authors affirm: “There is basically no difference between the P11 curves. For P12/ P11, P33/ P11 and P34/ P11, the variation patterns of the deviations between the two models are similar to that of P11, and the absolute differences of the two models are within 0.02. The calculated results of octagonal small particle show higher consistency than those of hexagonal prism small particle.” It should be better and more meaningful to add plots where the differences between results obtained using different methods are shown. It is impossible to quantify  differences using the plots shown in figures 5 to 10.

14)  Pag. 11 line 280. “…. coincident; When …” Substitute “;” with ” but”.

15)  Pag. 14 lines 344- 347. In “Author contributions” there are only initials, Names and Surnames are missing.

16)  Pag 14 – 15, References.  In references 7, 13, 14, 17, 18 and 25 there are only initials, Names and Surnames are missing.

Author Response

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Reviewer 2 Report

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Author Response

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Round 2

Reviewer 2 Report

The paper is improved after revisions and can be published in present form.